Hi,

thanks for the kind words both from Maxon and the community. I am looking forward to my upcoming adventures with the SDK Team and Cinema community.

Cheers,
Ferdinand

Hello @holgerbiebrach,

please excuse the wait. So, this is possible in Python and quite easy to do. This new behavior is just the old dialog folding which has been reworked a little bit. I have provided a simple example at the end of the posting. There is one problem regarding title bars which is sort of an obstacle for plugin developers which want to distribute their plugins, it is explained in the example below.

I hope this helps and cheers,
Ferdinand

The result:

The code:

"""Example for a command plugin with a foldable dialog as provided with the
Asset Browser or Coordinate Manger in Cinema 4D R25.

The core of this is just the old GeDialog folding mechanic which has been
changed slightly with R25 as it will now also hide the title bar of a folded
dialog, i.e., the dialog will be hidden completely.

The structure shown here mimics relatively closely what the Coordinate Manger
does. There is however one caveat: Even our internal implementations do not
hide the title bar of a dialog when unfolded. Instead, this is done via 
layouts, i.e., by clicking onto the ≡ icon of the dialog and unchecking the
"Show Window Title" option and then saving such layout. If you would want
to provide a plugin which exactly mimics one of the folding managers, you
would have to either ask your users to take these steps or provide a layout.

Which is not ideal, but I currently do not see a sane way to hide the title
bar of a dialog. What you could do, is open the dialog as an async popup which 
would hide the title bar. But that would also remove the ability to dock the 
dialog. You could then invoke `GeDialog.AddGadegt(c4d.DIALOG_PIN, SOME_ID)`to 
manually add a pin back to your dialog, so that you can dock it. But that is 
not how it is done internally by us, as we simply rely on layouts for that.
"""

import c4d


class ExampleDialog (c4d.gui.GeDialog):
    """Example dialog that does nothing.

    The dialog itself has nothing to do with the implementation of the
    folding.
    """
    ID_GADGETS_START = 1000
    ID_GADGET_GROUP = 0
    ID_GADGET_LABEL = 1
    ID_GADGET_TEXT = 2

    GADGET_STRIDE = 10
    GADEGT_COUNT = 5

    def CreateLayout(self) -> bool:
        """Creates dummy gadgets.
        """
        self.SetTitle("ExampleDialog")
        flags = c4d.BFH_SCALEFIT

        for i in range(self.GADEGT_COUNT):
            gid = self.ID_GADGETS_START + i * self.GADGET_STRIDE
            name = f"Item {i}"

            self.GroupBegin(gid + self.ID_GADGET_GROUP, flags, cols=2)
            self.GroupBorderSpace(5, 5, 5, 5)
            self.GroupSpace(2, 2)
            self.AddStaticText(gid + self.ID_GADGET_LABEL, flags, name=name)
            self.AddEditText(gid + self.ID_GADGET_TEXT, flags)
            self.GroupEnd()
        return True


class FoldingManagerCommand (c4d.plugins.CommandData):
    """Provides the implementation for a command with a foldable dialog.
    """
    ID_PLUGIN = 1058525
    REF_DIALOG = None

    @property
    def Dialog(self) -> ExampleDialog:
        """Returns a class bound ExampleDialog instance.
        """
        if FoldingManagerCommand.REF_DIALOG is None:
            FoldingManagerCommand.REF_DIALOG = ExampleDialog()

        return FoldingManagerCommand.REF_DIALOG

    def Execute(self, doc: c4d.documents.BaseDocument) -> bool:
        """Folds or unfolds the dialog.

        The core of the folding logic as employed by the Asset Browser
        or the Coordinate manager in R25.
        """
        # Get the class bound dialog reference.
        dlg = self.Dialog
        # Fold the dialog, i.e., hide it if it is open and unfolded. In C++
        # you would also want to test for the dialog being visible with
        # GeDialog::IsVisible, but we cannot do that in Python.
        if dlg.IsOpen() and not dlg.GetFolding():
            dlg.SetFolding(True)
        # Open or unfold the dialog. The trick here is that calling
        # GeDialog::Open will also unfold the dialog.
        else:
            dlg.Open(c4d.DLG_TYPE_ASYNC, FoldingManagerCommand.ID_PLUGIN)

        return True

    def RestoreLayout(self, secret: any) -> bool:
        """Restores the dialog on layout changes.
        """
        return self.Dialog.Restore(FoldingManagerCommand.ID_PLUGIN, secret)

    def GetState(self, doc: c4d.documents.BaseDocument) -> int:
        """Sets the command icon state of the plugin.

        This is not required, but makes it a bit nicer, as it will indicate
        in the command icon when the dialog is folded and when not.
        """
        dlg = self.Dialog
        result = c4d.CMD_ENABLED
        if dlg.IsOpen() and not dlg.GetFolding():
            result |= c4d.CMD_VALUE

        return result


def RegisterFoldingManagerCommand() -> bool:
    """Registers the example.
    """
    return c4d.plugins.RegisterCommandPlugin(
        id=FoldingManagerCommand.ID_PLUGIN,
        str="FoldingManagerCommand",
        info=c4d.PLUGINFLAG_SMALLNODE,
        icon=None,
        help="FoldingManagerCommand",
        dat=FoldingManagerCommand())


if __name__ == '__main__':
    if not RegisterFoldingManagerCommand():
        raise RuntimeError(
            f"Failed to register {FoldingManagerCommand} plugin.")

Dear Community,

this question reached us via email-support in the context of C++, but I thought the answer might be interesting for other users too.

The underlying question in this case was how to project points from object or world space into the texture space of an object with UV data. I am showing here deliberately an approach that can be followed both in C++ and Python, so that all users can benefit from this. In C++ one has also the option of using VolumeData and its methods VolumeData::GetUvw or VolumeData::ProjectPoint but must then either implement a volume shader (as otherwise the volume data attached to the ChannelData passed to ShaderData::Output will be nullptr), or use VolumeData:: AttachVolumeDataFake to access ::ProjectPoint. There is however no inherent necessity to take this shader bound route as shown by the example.

Cheers,
Ferdinand

Result

The script has created a texture with red pixels for the intersection points of the rays cast from each vertex of the spline towards the origin of the polygon object. The script also created the null object rays to visualize the rays which have been cast.

raycast_texture.c4d : The scene file.

Code

You must save the script to disk before running it, as the script infers from the script location the place to save the generated texture to.

"""Demonstrates how to project points from world or object space to UV space.

This script assumes that the user has selected a polygon object and a spline object in the order
mentioned. The script projects the points of the spline object onto the polygon object and creates
a texture from the UV coordinates of the projected points. The texture is then applied to the
polygon object.

The script uses the `GeRayCollider` class to find the intersection of rays cast from the points of
the spline object to the polygon object. The UV coordinates of the intersection points are then
calculated using the `HairLibrary` class. In the C++ API, one should use maxon::
GeometryUtilsInterface::CalculatePolygonPointST() instead.

Finally, using GeRayCollider is only an example for projecting points onto the mesh. In practice,
any other method can be used as long as it provides points that lie in the plane(s) of a polygon.

The meat of the example is in the `main()` function. The other functions are just fluff.
"""

import os
import c4d
import mxutils
import uuid

from mxutils import CheckType

doc: c4d.documents.BaseDocument  # The currently active document.
op: c4d.BaseObject | None  # The primary selected object in `doc`. Can be `None`.

def CreateTexture(points: list[c4d.Vector], path: str, resolution: int = 1000) -> None:
    """Creates a texture from the given `points` and saves it to the given `path`.

    Parameters:
        path (str): The path to save the texture to.
        points (list[c4d.Vector]): The points to create the texture from.
    """
    # Check the input values for validity.
    if os.path.exists(path):
        raise FileExistsError(f"File already exists at path: {path}")
    if not path.endswith(".png"):
        raise ValueError("The path must end with '.png'.")

    # Create a drawing canvas to draw the points on.
    canvas: c4d.bitmaps.GeClipMap = CheckType(c4d.bitmaps.GeClipMap())
    if not canvas.Init(resolution, resolution, 24):
        raise MemoryError("Failed to initialize GeClipMap.")

    # Fill the canvas with white.
    canvas.BeginDraw()
    canvas.SetColor(255, 255, 255)
    canvas.FillRect(0, 0, resolution, resolution)

    # Draw the points on the canvas.
    canvas.SetColor(255, 0, 0)
    for p in points:
        x: int = int(p.x * resolution)
        y: int = int(p.y * resolution)
        x0: int = max(0, x - 1)
        y0: int = max(0, y - 1)
        x1: int = min(resolution, x + 1)
        y1: int = min(resolution, y + 1)
        canvas.FillRect(x0, y0, x1, y1)

    canvas.EndDraw()

    # Save the canvas to the given path.
    bitmap: c4d.bitmaps.BaseBitmap = CheckType(canvas.GetBitmap())
    bitmap.Save(path, c4d.FILTER_PNG)

    c4d.bitmaps.ShowBitmap(bitmap)

def ApplyTexture(obj: c4d.BaseObject, path: str) -> None:
    """Applies the texture at the given `path` to the given `obj`.
    """
    CheckType(obj, c4d.BaseObject)

    # Check the input values for validity.
    if not os.path.exists(path):
        raise FileNotFoundError(f"File does not exist at path: {path}")

    # Create a material and apply the texture to it.
    material: c4d.BaseMaterial = CheckType(c4d.BaseMaterial(c4d.Mmaterial), c4d.BaseMaterial)
    obj.GetDocument().InsertMaterial(material)

    shader: c4d.BaseShader = CheckType(c4d.BaseShader(c4d.Xbitmap), c4d.BaseShader)
    shader[c4d.BITMAPSHADER_FILENAME] = path
    material.InsertShader(shader)
    material[c4d.MATERIAL_COLOR_SHADER] = shader
    material[c4d.MATERIAL_PREVIEWSIZE] = c4d.MATERIAL_PREVIEWSIZE_1024

    # Apply the material to the object.
    tag: c4d.TextureTag = CheckType(obj.MakeTag(c4d.Ttexture))
    tag[c4d.TEXTURETAG_PROJECTION] = c4d.TEXTURETAG_PROJECTION_UVW
    tag[c4d.TEXTURETAG_MATERIAL] = material

def CreateDebugRays(spline: c4d.SplineObject, p: c4d.Vector) -> None:
    """Adds spline objects to the document to visualize the rays from the given `p` to the points of
    the given `spline`.
    """
    doc: c4d.documents.BaseDocument = CheckType(spline.GetDocument(), c4d.documents.BaseDocument)
    rays: c4d.BaseObject = c4d.BaseObject(c4d.Onull)
    rays.SetName("Rays")
    doc.InsertObject(rays)

    for q in spline.GetAllPoints():
        ray: c4d.SplineObject = c4d.SplineObject(2, c4d.SPLINETYPE_LINEAR)
        ray.SetPoint(0, p)
        ray.SetPoint(1, q * spline.GetMg())
        ray.Message(c4d.MSG_UPDATE)
        ray.InsertUnder(rays)

def main() -> None:
    """Carries out the main logic of the script.
    """
    # Check the object selection for being meaningful input.
    selected: list[c4d.BaseObject] = doc.GetActiveObjects(c4d.GETACTIVEOBJECTFLAGS_SELECTIONORDER)
    if (len(selected) != 2 or not selected[0].CheckType(c4d.Opolygon) or
        not selected[1].CheckType(c4d.Ospline)):
        raise ValueError("Please select a polygon object and a spline object.")

    polygonObject, splineObject = selected

    # Get the uvw tag, the points, and the polygons of the polygon object.
    uvwTag: c4d.UvwTag = mxutils.CheckType(polygonObject.GetTag(c4d.Tuvw))
    points: list[c4d.Vector] = [polygonObject.GetMg() * p for p in polygonObject.GetAllPoints()]
    polys: list[c4d.CPolygon] = polygonObject.GetAllPolygons()

    # We are casting here in a dumb manner towards the center of the polygon object. In practice,
    # one should cast rays towards the plane of the polygon object. Or even better, use another
    # method to project the points onto the polygon object, as GeRayCollider is not the most 
    # efficient thing in the world.
    rayTarget: c4d.Vector = polygonObject.GetMg().off
    CreateDebugRays(splineObject, rayTarget)

    # Initialize the GeRayCollider to find the intersection of rays cast from the points of the
    # spline object to the polygon object.
    collider: c4d.utils.GeRayCollider = c4d.utils.GeRayCollider()
    if not collider.Init(polygonObject):
        raise MemoryError("Failed to initialize GeRayCollider.")


    # Init our output list and iterate over the points of the spline object.
    uvPoints: list[c4d.Vector] = []
    for p in splineObject.GetAllPoints():

        # Transform the point from object to world space (q) and then to the polygon object's space
        # (ro). Our ray direction always points towards the center of the polygon object.
        q: c4d.Vector = splineObject.GetMg() * p
        ro: c4d.Vector = ~polygonObject.GetMg() * q
        rd: c4d.Vector = rayTarget - ro

        # Cast the ray and check if it intersects with the polygon object.
        if not collider.Intersect(ro, rd, 1E6) or collider.GetIntersectionCount() < 1:
            continue
        
        # Get the hit position and the polygon ID of the intersection.
        hit: dict = collider.GetNearestIntersection()
        pos: c4d.Vector = mxutils.CheckType(hit.get("hitpos", None), c4d.Vector)
        pid: int = mxutils.CheckType(hit.get("face_id", None), int)

        # One mistake would be now to use the barycentric coordinates that are in the intersection
        # data, as Cinema uses an optimized algorithm to interpolate in a quad and not the standard
        # cartesian-barycentric conversion. In Python these polygon weights are only exposed in a 
        # bit weird place, the hair library. In C++ these barycentric coordinates make sense because
        # there exist methods to convert them to weights. In Python the barycentric coordinates are
        # pretty much useless as we do not have such a conversion function here.

        # Compute the weights s, t for the intersection point in the polygon.
        s, t = c4d.modules.hair.HairLibrary().GetPolyPointST(
            pos, points[polys[pid].a], points[polys[pid].b],
                 points[polys[pid].c], points[polys[pid].d], True)

        # Get the uv polygon and bilinearly interpolate the coordinates using the weights. It would
        # be better to use the more low-level variable tag data access functions in VariableTag 
        # than UvwTag.GetSlow() in a real-world scenario.
        uvw: list[c4d.Vector] = list(uvwTag.GetSlow(pid).values())
        t0: c4d.Vector = c4d.utils.MixVec(uvw[0], uvw[1], s)
        t1: c4d.Vector = c4d.utils.MixVec(uvw[3], uvw[2], s)
        uv: c4d.Vector = c4d.utils.MixVec(t0, t1, t)

        # Append the UV coordinates to the output list.
        uvPoints.append(uv)

    # Write the UV coordinates to a texture and apply it to the polygon object.
    path: str = os.path.join(os.path.dirname(__file__), f"image-{uuid.uuid4()}.png")
    CreateTexture(uvPoints, path, resolution=1024)
    ApplyTexture(polygonObject, path)

    c4d.EventAdd()


if __name__ == '__main__':
    main()

Hi,

that your script is not working has not anything to do with pseudo decimals, but the fact that you are treating numbers as strings (which is generally a bad idea) in a not very careful manner. When you truncate the string representation of a number which is represented in scientific notation (with an exponent), then you also truncate that exponent and therefor change the value of the number.

To truncate a float you can either take the floor of my_float * 10 ** digits and then divide by 10 ** digits again or use the keyword round.

data = [0.03659665587738824,
        0.00018878623163019122,
        1.1076812650509394e-03,
        1.3882258325566638e-06]

for n in data:
    rounded = round(n, 4)
    floored = int(n * 10000) / 10000
    print(n, rounded, floored)

0.03659665587738824 0.0366 0.0365
0.00018878623163019122 0.0002 0.0001
0.0011076812650509394 0.0011 0.0011
1.3882258325566637e-06 0.0 0.0
[Finished in 0.1s]

Cheers
zipit

Dear community,

We will have to touch multiple parts of developers.maxon.net on the 18.01.2024 and 19.01.2024 22.01.2024. This will result in outages of our documentation and the forum these days. I will try to keep the outage times to a minimum and it will certainly not span the whole two days. But especially one task I will do on Friday might take hours to complete and I can only do that on a forum which is in maintenance mode.

Please make sure to download a recent offline documentation in case you plan to do extended development work the next two days. As a result, forum support might also be delayed on these days.

Cheers,
Ferdinand

Hi,

as @Cairyn said the problem is unreachable code. I also just saw now that you did assign the same ID to all your buttons in your CreateLayout(). Ressource and dialog element IDs should be unique. I would generally recommend to define your dialogs using a resource, but here is an example on how to do it in code.

BUTTON_BASE_ID = 1000
BUTTON_NAMES = ["Button1", "Button2", "Button3", "Button4", "Button5"]
BUTTON_DATA = {BUTTON_BASE_ID + i: name for i, name in enumerate(BUTTON_NAMES)}

class MyDialog(gui.GeDialog):

    def CreateLayout(self):
        """
        """
        self.GroupBegin(id=1013, flags=c4d.BFH_SCALEFIT, cols=5, rows=4)
        for element_id, element_name in BUTTON_DATA.items():
            self.AddButton(element_id, c4d.BFV_MASK, initw=100, 
                           name=element_name)
        self.GroupEnd()
        return True

    def Command(self, id, msg):
        """
        """
        if id == BUTTON_BASE_ID:
            print "First button has been clicked"
        elif id == BUTTON_BASE_ID + 1:
            print "Second button has been clicked"
        # ...
        if id in BUTTON_DATA.keys(): # or just if id in BUTTON_DATA
            self.Close()
        return True

Dear development community,

On September the 10th, 2024, Maxon Computer released Cinema 4D 2025.0.0. For an overview of the new features of Cinema 4D 2025.0, please refer to the release announcement. Alongside this release, a new Cinema 4D SDK and SDK documentation have been released, reflecting the API changes for 2025.0.0. The major changes are:

C++ API

• What was formerly has been know as the Classic API has been deprecated in favour of the Cinema API. Alongside this a new cinema namespace has been introduced which contains all the entities which were formerly in the anonymous global namespace known as the Classic API. Plugin authors must adopt their code to this new API, although the changes are not nearly as extensive as for 2024. See the 2025 migration guide for details. Code examples and documentation have been updated to now refer to a Cinema API.
• 2025 uses OCIO as the default color management mode, brings an improved color picker, and made general improvements to the consistency of the OCIO implementation. This had some effects on the underlying OCIO API which are reflected in two new code examples in the OCIO Manual and a new plugin in the SDK.

Python API

• Python also received the update from Classic to Cinema API. But here the change was more of a cosmetic nature confined to the documentation. The c4d package remains the home for all formerly Classic and now Cinema API entities.
• The mxutils package received updates around standardized scene traversal, random number generation, and more.
• Graph descriptions now support variadic ports of arbitrary complexity and explicit port references.

Head to our download section for the newest SDK downloads, or the C++ and Python API change notes for an in detail overview of the changes.

We discovered late in the cycle bugs in the Asset API code examples and OCIO code in the Python SDK. Which is why the publication of the Python SDK and GitHub code examples has been postponed until these bugs are fixed. They should be ready latest by Friday the 13th of September. But the Python online documentation is accessible and error free (to our knowledge).

We had to make some last minute changes to the C++ SDK regarding OCIO code examples. Only the extended C++ SDK contains these changes. The application provided sdk.zip will catch up with the next release of Cinema 4D.

Happy rendering and coding,
the Maxon SDK Team

Cloudflare unfortunately still does interfere with our server cache. And you might have to refresh your cache manually.

When you are not automatically redirected to the new versions, and also do not see 2024.5 in the version selector, please press CTRL + F5 or press CTRL and click on the reload icon of your browser anywhere on developers.maxon.net/docs/ to refresh your cache. You only have to do this once and it will apply to all documentations at once. Otherwise your cache will automatically update latest by 19/07/2024 00:00.

Hi,

sorry for all the confusion. You have to pass actual instances of objects. The following code does what you want (and this time I actually tried it myself ;)).

import c4d

def main():
    """
    """
    bc = doc.GetAllTextures(ar=doc.GetMaterials())
    for cid, value in bc:
        print cid, value

if __name__=='__main__':
   main()

Cheers,
zipit

Hi,

you use GetActiveDocument() in a NodeData environment. You cannot do this, since nodes are also executed when their document is not the active document (while rendering for example - documents get cloned for rendering).

Cheers
zipit

Hi,

you have to invoke AddUserArea and then attach an instance of your implemented type to it. Something like this:

my_user_area = MyUserAreaType()
self.AddUserArea(1000,*other_arguments)
self.AttachUserArea(my_user_area, 1000)

I have attached an example which does some things you are trying to do (rows of things, highlighting stuff, etc.). The gadget is meant to display a list of boolean values and the code is over five years old. I had a rather funny idea of what good Python should look like then and my attempts of documentation were also rather questionable. I just wrapped the gadget into a quick example dialog you could run as a script. I did not maintain the code, so there might be newer and better ways to do things now.

Also a warning: GUI stuff is usually a lot of work and very little reward IMHO.

Cheers
zipit

import c4d
import math
import random

from c4d import gui

# Pattern Gadget
IDC_SELECTLOOP_CELLSIZE = [32, 32]
IDC_SELECTLOOP_GADGET_MINW = 400
IDC_SELECTLOOP_GADGET_MINH = 32

class ExampleDialog(gui.GeDialog):
    """
    """
    def CreateLayout(self):
        """
        """

        self.Pattern = c4d.BaseContainer()
        for i in range(10):
            self.Pattern[i] = random.choice([True, False])
        self.PatternSize = len(self.Pattern)

        self.gadget = Patterngadget(host=self)
        self.AddUserArea(1000, c4d.BFH_FIT, 400, 32)
        self.AttachUserArea(self.gadget, 1000)
        return True

class Patterngadget(gui.GeUserArea):
    """
    A gui gadget to modify and display boolean patterns.
    """

    def __init__(self, host):
        """
        :param host: The hosting BaseToolData instance
        """
        self.Host = host
        self.BorderWidth = None
        self.CellPerColumn = None
        self.CellWidht = IDC_SELECTLOOP_CELLSIZE[0]
        self.CellHeight = IDC_SELECTLOOP_CELLSIZE[1]
        self.Columns = None
        self.Height = None
        self.Width = None
        self.MinHeight = IDC_SELECTLOOP_GADGET_MINH
        self.MinWidht = IDC_SELECTLOOP_GADGET_MINW
        self.MouseX = None
        self.MouseY = None

    """------------------------------------------------------------------------
        Overridden methods
        --------------------------------------------------------------------"""

    def Init(self):
        """
        Init the gadget.
        :return : Bool
        """
        self._get_colors()
        return True

    def GetMinSize(self):
        """
        Resize the gadget
        :return : int, int
        """
        return int(self.MinWidht), int(self.MinHeight)

    def Sized(self, w, h):
        """
        Get the gadgets height and width
        """
        self.Height, self.Width = int(h), int(w)
        self._fit_gadget()

    def Message(self, msg, result):
        """
        Fetch and store mouse over events
        :return : bool
        """
        if msg.GetId() == c4d.BFM_GETCURSORINFO:
            base = self.Local2Screen()
            if base:
                self.MouseX = msg.GetLong(c4d.BFM_DRAG_SCREENX) - base['x']
                self.MouseY = msg.GetLong(c4d.BFM_DRAG_SCREENY) - base['y']
                self.Redraw()
                self.SetTimer(1000)
        return gui.GeUserArea.Message(self, msg, result)

    def InputEvent(self, msg):
        """
        Fetch and store mouse clicks
        :return : bool
        """
        if not isinstance(msg, c4d.BaseContainer):
            return True
        if msg.GetLong(c4d.BFM_INPUT_DEVICE) == c4d.BFM_INPUT_MOUSE:
            if msg.GetLong(c4d.BFM_INPUT_CHANNEL) == c4d.BFM_INPUT_MOUSELEFT:
                base = self.Local2Global()
                if base:
                    x = msg.GetLong(c4d.BFM_INPUT_X) - base['x']
                    y = msg.GetLong(c4d.BFM_INPUT_Y) - base['y']
                    pid = self._get_id(x, y)
                    if pid <= self.Host.PatternSize:
                        self.Host.Pattern[pid] = not self.Host.Pattern[pid]
                        self.Redraw()
        return True

    def Timer(self, msg):
        """
        Timer loop to catch OnMouseExit
        """
        base = self.Local2Global()
        bc = c4d.BaseContainer()
        res = gui.GetInputState(c4d.BFM_INPUT_MOUSE,
                                c4d.BFM_INPUT_MOUSELEFT, bc)
        mx = bc.GetLong(c4d.BFM_INPUT_X) - base['x']
        my = bc.GetLong(c4d.BFM_INPUT_Y) - base['y']
        if res:
            if not (mx >= 0 and mx <= self.Width and
                    my >= 0 and my <= self.Height):
                self.SetTimer(0)
                self.Redraw()

    def DrawMsg(self, x1, y1, x2, y2, msg):
        """
        Draws the gadget
        """
        # double buffering
        self.OffScreenOn(x1, y1, x2, y2)
        # background & border
        self.DrawSetPen(self.ColBackground)
        self.DrawRectangle(x1, y1, x2, y2)
        if self.BorderWidth:
            self.DrawBorder(c4d.BORDER_THIN_IN, x1, y1,
                            self.BorderWidth + 2, y2 - 1)
        # draw pattern
        for pid, state in self.Host.Pattern:
            x, y = self._get_rect(pid)
            self._draw_cell(x, y, state, self._is_focus(x, y))

    """------------------------------------------------------------------------
        Public methods
        --------------------------------------------------------------------"""

    def Update(self, cid=None):
        """
        Update the gadget.
        :param cid: A pattern id to toggle.
        """
        if cid and cid < self.Host.PatternSize:
            self.Host.Pattern[cid] = not self.Host.Pattern[cid]
        self._fit_gadget()
        self.Redraw()

    """------------------------------------------------------------------------
        Private methods
        --------------------------------------------------------------------"""

    def _get_colors(self, force=False):
        """
        Set the drawing colors.
        :return : Bool
        """
        self.ColScale = 1.0 / 255.0
        if self.IsEnabled() or force:
            self.ColBackground = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellActive = c4d.GetViewColor(
                c4d.VIEWCOLOR_ACTIVEPOINT) * 0.9
            self.ColCellFocus = self._get_color_vector(c4d.COLOR_BGFOCUS)
            self.ColCellInactive = self._get_color_vector(c4d.COLOR_BGEDIT)
            self.ColEdgeDark = self._get_color_vector(c4d.COLOR_EDGEDK)
            self.ColEdgeLight = self._get_color_vector(c4d.COLOR_EDGELT)
        else:
            self.ColBackground = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellActive = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellFocus = self._get_color_vector(c4d.COLOR_BG)
            self.ColCellInactive = self._get_color_vector(c4d.COLOR_BG)
            self.ColEdgeDark = self._get_color_vector(c4d.COLOR_EDGEDK)
            self.ColEdgeLight = self._get_color_vector(c4d.COLOR_EDGELT)
        return True

    def _get_cell_pen(self, state, _is_focus):
        """
        Get the color for cell depending on its state.
        :param state   : The state
        :param _is_focus : If the cell is hoovered.
        :return        : c4d.Vector()
        """
        if state:
            pen = self.ColCellActive
        else:
            pen = self.ColCellInactive
        if self.IsEnabled() and _is_focus:
            return (pen + c4d.Vector(2)) * 1/3
        else:
            return pen

    def _draw_cell(self, x, y, state, _is_focus):
        """
        Draws a gadget cell.
        :param x:       local x
        :param y:       local y
        :param state:   On/Off
        :param _is_focus: MouseOver state
        """
        # left and top bright border
        self.DrawSetPen(self.ColEdgeLight)
        self.DrawLine(x, y, x + self.CellWidht, y)
        self.DrawLine(x, y, x, y + self.CellHeight)
        # bottom and right dark border
        self.DrawSetPen(self.ColEdgeDark)
        self.DrawLine(x, y + self.CellHeight - 1, x +
                      self.CellWidht - 1, y + self.CellHeight - 1)
        self.DrawLine(x + self.CellWidht - 1, y, x +
                      self.CellWidht - 1, y + self.CellHeight - 1)
        # cell content
        self.DrawSetPen(self._get_cell_pen(state, _is_focus))
        self.DrawRectangle(x + 1, y + 1, x + self.CellWidht -
                           2, y + self.CellHeight - 2)

    def _get_rect(self, pid, offset=1):
        """
        Get the drawing rect for an array id.
        :param pid    : the pattern id
        :param offset : the pixel border offset
        :return       : int, int
        """
        pid = int(pid)
        col = pid / self.CellPerColumn
        head = pid % self.CellPerColumn
        return self.CellWidht * head + offset, self.CellHeight * col + offset

    def _get_id(self, x, y):
        """
        Get the array id for a coord within the gadget.
        :param x : local x
        :param y : local y
        :return  : int
        """
        col = (y - 1) / self.CellHeight
        head = (x - 1) / self.CellWidht
        return col * self.CellPerColumn + head

    def _is_focus(self, x, y):
        """
        Test if the cell coords are under the cursor.
        :param x : local x
        :param y : local y
        :return  : bool
        """
        if (self.MouseX >= x and self.MouseX <= x + self.CellWidht and
                self.MouseY >= y and self.MouseY <= y + self.CellHeight):
            self.MouseX = c4d.NOTOK
            self.MouseY = c4d.NOTOK
            return True
        else:
            return False

    def _fit_gadget(self):
        """
        Fit the gadget size to the the array
        """
        oldHeight = self.MinHeight
        self.CellPerColumn = int((self.Width - 2) / self.CellWidht)
        self.Columns = math.ceil(
            self.Host.PatternSize / self.CellPerColumn) + 1
        self.MinHeight = int(IDC_SELECTLOOP_GADGET_MINH * self.Columns) + 3
        self.MinWidht = int(IDC_SELECTLOOP_GADGET_MINW)
        self.BorderWidth = self.CellWidht * self.CellPerColumn
        if oldHeight != self.MinHeight:
            self.LayoutChanged()

    def _get_color_vector(self, cid):
        """
        Get a color vector from a color ID.
        :param cid : The color ID
        :return    : c4d.Vector()
        """
        dic = self.GetColorRGB(cid)
        if dic:
            return c4d.Vector(float(dic['r']) * self.ColScale,
                              float(dic['g']) * self.ColScale,
                              float(dic['b']) * self.ColScale)
        else:
            return c4d.Vector()

if __name__ == "__main__":
    dlg = ExampleDialog()
    dlg.Open(c4d.DLG_TYPE_ASYNC, defaultw=400, defaulth=400)

Hey @BruceC,

uff, that is a lot of points. I'll try to comb through most of it, but I do not have that much time today. Feel free to ask for clarifications where I left out things.

Currently, I do this in the tag plugin's Execute() function. The tag plugin remembers the vertex color tag's pointer (initialized as nullptr) and dirty checksum (by C4DAtom::GetDirty(), and initialized as 0).

Never user pointers to long term keep track of scene elements. Something not being nullptr does not mean you point to valid data. The node you point to could be long deleted, and then you point to garbage and access attempts will then result in access violations and a crash. Either use a BaseLink to store a reference to a scene element, or use a weak pointer. I.e., a pointer which becomes invalid when the pointed data is being deleted. You can for example see here how to use a maxon::WeakRawPtr.

However, I found ExecutePasses() called in PrerollToTime() triggers the tag plugin's Execute() function (I think this is the cloned tag in the cloned document), and Execute() function tries to read the linked vertex color tag at the speficied frame again, so PrerollToTime() -> ExecutePasses() is called again, and triggers a new cloned tag in a new cloned document to run its Execute(), and so on.

Yes, that is true and a common problem (not only in Cinema 4D). The superficial reason is that my preroll code example also passes True for the third argument expressions (effectively API slang for tags). When you would pass there false, your tag would not be executed again. But also all other tags would not be executed (which is likely not what you want). The solution to this can be registering a plugin ID, e.g., ID_FOO_PLUGIN_IS_COMPUTE_PASS. When you then clone your document, or execute the passes on an existing document, you write under that ID for example a bool into the data container of the document. Your tags Execute(tag, ...) then gets the document from tag and checks for that flag being present, to stop what it does that causes the infinite update loop. When operating on a document not owned by you, you would then delete that flag or set it to false after you manually invoked the passes, so that future updates made by Cinema 4D (which owns and operates the document) then take the 'normal' route.

The better solution is to generally design things in a manner that such infinite update loops cannot happen in the first place. I do not understand your problem well enough to give more concrete advice here. These scenarios are also not always avoidable.

According to the sample code PrerollToTime(), the lastFrame (the target frame) must not be earlier than the current scene's time.

The preroll function was just an example, not something you must follow to the letter. There is also a little bug I just see now, it should be of course if (lastFrame < firstFrame - 1). But the general idea is, that when you have a scene with simulations, i.e., stuff like Pyro or particles, where the state of the current frame depends on the last frame, you must basically cycle through all the correct scene states to get to that state. You can of course also jump to a previous point, but then you do not have to sim from NOW to FUTURE but from 0 to PREVIOUS.

Prerolling is not necessary when the scene does not contain any simulations, e.g., just key framed position animations, all simulations are cached, or you do not care about simulations and their impact on the rest of scene. Given what kind of plugins you do develop, you likely want to preroll.

Just to stress this again: Prerolling can be extremely expensive. When the user has a scene with 300 frames of Pyro simulations worth 30 minutes of computing, and you try to preroll half of it, your preroll function will run for 15 minutes.

What to do here, really depends on the exact case. Generally you try to avoid having to reach into the future or the past, as this is often a big no-no. The most common "pro" solution to that is caching. E.g., that you write yourself a vertex color cache in your case. When you only need to reach into the past, and this only applies in rendering, you could also effectively hide this from the user, as you must have passed and naturally calculated that value before (and therefore need no explicit cache recording).

Will answer the (2) portion on Monday, running a bit out of Friday time right now.

Cheers,
Ferdinand

Hey @mogh,

that could be that I was wrong. But it was at least not an unintentional typo. That is how I remembered it and what is also usually the case in Cinema 4D. v3 is an alias for the k component of an i, j, k frame, i.e., the "z-axis". This is usually considered to be "the normal", i.e., when one constructs a frame, one makes it so that v3/k becomes the normal of what one is constructing that frame for. And to be verbose here, frame (of reference) is just some math slang for a coordinate system, i.e., what on a more general level is also called a "transform", or even more generic and how Cinema 4D handles it, a "matrix".

Bottom line is here, when v1 works for you as a normal, just use it, there is nothing which inherently makes k/v3 "the normal" of a frame. Maxime also touched spline transport some time ago, it could be that he switched things around.

There is only the Matrix Manual in Python, in C++ is nothing at all. Users are just supposed "to know" such stuff. I never find the time to do more than what I once did there. And just as warning, the normals of a spline are usually not what non-math people expect them to be, due to the fact that they are defined by curvature and that the concept of inflection points does exist. We once talked here about this, including an illustration.

That is why in CGI the normals of a spline are usually not the normals, but the parallel transport of some normal plus some upvector which determines the initial orientation. E.g., SplineHelp realizes parallel transport, so that you can for example have an "outline" of a spline which makes sense for artists. But as you might have noticed in the past as a user, outlining a spline does not always produce results a human would consider correct. Just search for "parallel tranport" here on the forum and limit the results to my user, we talked many times about it, including code examples etc.

So, long story short again, there is no mathematical way to compute the "perfect" normals for a spline, at least what humans consider this to be. And depending on the spline and the fanciness with which you implement parallel transport, you might be subject to normal banking and/or flipping issues. So, SplineHelp tries to give you normals/frames that humans would consider correct, but the quality of its efforts might vary.

Cheers,
Ferdinand

Hey @BruceC,

Thank you for reaching out to us. Let's split these effectively two questions into two parts.

Evaluating a BaseDocument at time #t

When you want to know the state of a scene at a time, #t, you can do this by setting the time of the document (BaseDocument::SetTime) and then executing its passes (BaseDocument::ExecutePasses), which is CInema 4D API slang for updating the scene state. This is configurable and can evaluate animations, build caches, and execute expressions, i.e., do the whole scene evaluation. But when you have a very heavy document, executing the passes is of course a not so cheap operation.

A more clever solution can be to manually interpolate animations - when that is all you need - via CCurve.GetValue. But that only works for animations that defined by keyframes and are decomposable into float values. The former is here not given for vertex colors, as you can only animate them procedurally.

This is all further complicated in a real life scenario, as being at frame t, then jumping to frame t + 10, and then just executing the passes might not be enough. The reason is because what you to query might be dependent on simulations; and your output will then be wrong when you just execute frame t and t + 10, instead of t, t + 1, ..., t + 10.

So, a preroll function could look like this:

using namespace cinema;

static maxon::Result<void> PrerollToTime(BaseDocument* const doc, const BaseTime& time)
{
  iferr_scope;
  CheckArgument(doc, "doc"_s, "Document is nullptr."_s);

  const Int32 fps = doc->GetFps();
  const Int32 firstFrame = doc->GetTime().GetFrame(fps) + 1;
  const Int32 lastFrame = time.GetFrame(fps);
  if (lastFrame < firstFrame - 1)
    return maxon::IllegalArgumentError(
      MAXON_SOURCE_LOCATION, "The target time is before the current time."_s);

  // Loop over all frames we need to reach #t and execute the passes. What to execute for each pass
  // (caches, animations, expressions) depends on what you want to achieve, and will of course have
  // an impact on the performance. Note that things likes cache building can have an impact on
  // animations and expressions, and vice versa. So, when one needs the 'true' scene state, one must
  // often calculate everything.
  for (Int32 frame = firstFrame; frame <= lastFrame; ++frame)
  {
    doc->SetTime(BaseTime(frame, fps));
    // Execute the passes for everything in the main thread (nullptr), use your thread instead when
    // you have one.
    if (!doc->ExecutePasses(nullptr, true, true, true, BUILDFLAGS::NONE))
      return maxon::UnexpectedError(MAXON_SOURCE_LOCATION, "Failed to execute pass."_s);
  }
  
  // For the last frame we should execute the passes twice, so that the scene can settle.
  if (!doc->ExecutePasses(nullptr, true, true, true, BUILDFLAGS::NONE))
      return maxon::UnexpectedError(MAXON_SOURCE_LOCATION, "Failed to execute pass."_s);

  // The document is now in the state of #time.
  return maxon::OK;
}

Finding a scene element #e in two scenes

I am a bit surprised that you ask that, as this is sort of the bread and butter for what you are doing. So, I might be misunderstanding you here. If that is so, please clarify what you mean.

The identity of scene elements is expressed in Cinema 4D by GeMarker. Such markers are given when objects are allocated (and by default also when copied) and are a hash of the creating machine's mac address, a timestamp and some secret sauce. An alternative way to retrieve the same data is BaseList2D::FindUniqueID(MAXON_CREATOR_ID) which just returns the raw data of the GeMarker obtainable via BaseList2D::GetMarker. When you copy scene elements or whole scenes, by default they are given new markers. You can prevent that with COPYFLAGS::PRIVATE_IDENTMARKER.

Never insert multiple nodes with the same marker into a scene.

An alternative could be to use links, i.e., a BaseLinks, for example in a BaseContainer stored with the document. But that is also just built on top of GeMarker.

Cheers,
Ferdinand

Hey @kbar,

I hope you are well! Since I just answered a similar question in another topic, I am also answering here. We never make any guarantees regarding when something will be released in SDKs. And more-over, we never name upcoming Cinema 4D versions explicitly or when they will arrive. This also includes seemingly insignificant information such as if the next version will be a minor or a major version increment.

Please note that you as Maxon Registered Developer are bound by an NDA and also cannot disclose such information to the public.

But yes, I am pretty sure Maxime meant the next upcoming release.

Cheers,
Ferdinand

Hello @patrick_cue,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

Getting Started

Before creating your next postings, we would recommend making yourself accustomed with our forum and support procedures. You did not do anything wrong, we point all new users to these rules.

• Forum Overview: Provides a broad overview of the fundamental structure and rules of this forum, such as the purpose of the different sub-forums or the fact that we will ban users who engage in hate speech or harassment.
• Support Procedures: Provides a more in detail overview of how we provide technical support for APIs here. This topic will tell you how to ask good questions and limits of our technical support.
• Forum Features: Provides an overview of the technical features of this forum, such as Markdown markup or file uploads.

It is strongly recommended to read the first two topics carefully, especially the section Support Procedures: Asking Questions.

About your First Question

Please do not use other topics for your support requests, especially when they are bug tickets. Asking a follow-up questions such as "when will this be fixed" or "does this also apply to situation B" in a foreign topic is allowed and even encouraged.

But a specific case with your specific code and data always warrants a new thread. Please also familiarize yourself with Support Procedures: Asking Questions, as while it its clear that you put effort into make yourself understood (thanks!), this is also bordering a bit on the too much information.

The bug tracked by the other topic, is that there is currently no way in the Python API to use c4d.documents.RenderDocument in an OCIO document (i.e., every document since 2025.0) and then display that bitmap with the correct colors via c4d.bitmaps.ShowBitmap. It is important to understand that:

The bitmap data generated is just fine, when you save the bitmap to disk, everything is correct. It is just that the Picture Viewer does not display it incorrectly.

The reason for that is that in Python OCIO is not fully exposed in 2025.1.0 and you cannot set the OCIO profiles of the rendered bitmap there. Internally, we have been working on an OCIO port for Python allowing for color conversions and more things, including OCIO managing bitmaps. We also added a function to bake a display and view transform into an sRGB image - another route how this RenderDocument issue can be solved.

The goal is to publish this with an upcoming version of the Python SDK, ideally the next, but as always we cannot make any guarantees. You cannot fix this issue yourself in 2025.1.0 and lower.

Cheers,
Ferdinand

@mogh said in How to receive the high definition / Interpolation version of a spline?:

from the above helper I only get the points the spline is set to (eg. adaptive 5°) but I perhaps want more points in between.

That is not correct. As I said, splines have theoretically infinite precision, you are only bound in practice by the floating point precision you use for your computations - double, i.e., 64 bit in Cinema 4D. You get in your code just the cache of your spline and iterate over its points. That is more or less the same as if you would have just called BaseObject.GetCache() on your SplineObject which I mentioned above.

When you want to interpolate your spline manually, you must use the interpolation methods of SplineHelp, e.g., GetMatrix, which is sort of the most potent of all, as it gives you a full frame for each sample (i.e., not just a point but also an orientation).

I have a hunch that the actual question is how to build the cache of a spline as if it would have higher interpolation settings. And for that you should copy your input (unless it is already a dangling, i.e., non-inserted node), change its settings, insert it into a dummy document, and then call ExecutePasses on that document. Then you can get the cache, and iterate over its points.

Cheers,
Ferdinand

import c4d

doc: c4d.documents.BaseDocument  # The currently active document.
op: c4d.BaseObject | None  # The primary selected object in `doc`. Can be `None`.

def main() -> None:
    """Called by Cinema 4D when the script is being executed.
    """
    if not op:
        return
    
    helper = c4d.utils.SplineHelp()
    if not helper.InitSplineWith(op, c4d.SPLINEHELPFLAGS_RETAINLINEOBJECT):
        raise RuntimeError("Could not initialize spline helper.")
    
    # Take exactly ten samples over the length of the spline, no matter how many vertices it has,
    # and how many points its current LineObject cache has.
    steps: int = 10
    for i in range(steps + 1):
        # Get a frame for the offset #t.
        t: float = i/float(steps)
        m: c4d.Matrix = helper.GetMatrix(t)

        # Print the #t, the point #p on the spline, its normal #n, tangent #t, and bi-tangent #bt.
        print(f"{t = }, p = {m.off}, n = {m.v3}, t = {m.v1}, bt = {m.v2}")

if __name__ == '__main__':
    main()

Hey @mogh,

that is not possible, nodes, i.e., NodeData, e.g., TagData, always need a description (and with that res file).

Cheers,
Ferdinand

Hey @mogh,

Thank you for reaching out to us. What do you mean with "low" detail? Something like the sampling angle of a spline in "adaptive" mode? The interpolation settings of a spline only apply when you quantize it, i.e., the degree of precision with which a SplineObject is being quantized into its LineObject cache (i.e., what is returned for BaseObject.GetCache() for a spline).

Splines themselves are just series of polynomials and therefore have no inherent precision. So, when you call for example SplineHelp.GetMatrix() to get all the metadata for an offset, you are not subject to the interpolation settings. That is within the limits of what computers can do regarding arithmetic of irrational numbers. You can quite quickly get subject to floating point precision problems when working with splines. If they are fixable and how to fix them, depends on the concrete case.

Cheers,
Ferdinand

When this is what you want, a Python Programming Tag has also a draw function, i.e., the scripting element inside Cinema 4D. Scripting elements make great prototypes for their full grown plugin counter part (for the Python tag that would be TagData) but can also be very potent on their own while providing phenomenally rapid development speed.

Hey,

A tag can draw into a viewport My line of thinking was that you want some form of automatism/ streamlined product. E.g., an "enable/disable comb drawing" button (CommandData) and then a node (TagData/ObjectData) actually implementing it. When you just want to have the ability to manually enhance a spline with some drawing decorations, a tag would be a very good choice.

Cheers,
Ferdinand