Hi,in another post I found a way to achieve my goal of converting the coordinate position to camera space and then scaling it to a small size so that he appears first.

this is new code:

def Draw(self,op, drawpass, bd, bh):
    
    
    if not op[c4d.S_MOTIONTRAIL_GTWO_DRAWENABLE]:
        return c4d.DRAWRESULT_OK
    #bd.SetMatrix_Matrix(None, c4d.Matrix())
    pmg = ~bd.GetMg()
    bd.SetMatrix_Camera()

    all_pos = self.parameters['all_pos']
    color_lis = self.parameters['color_lis']
    point_size = op[c4d.S_MOTIONTRAIL_GTWO_POINTSIZE]
    bd.SetPointSize(point_size)
    for per_pos,color in zip(all_pos,color_lis):
        bd.SetPen(color)
        cnt = len(per_pos)
        temp_lis = []
        for i in xrange(cnt-1):
            c = (pmg * per_pos[i]).GetNormalized() * 20
            f = (pmg * per_pos[i+1]).GetNormalized() * 20
            bd.DrawLine(c,f,c4d.NOCLIP_D)
            temp_lis.append(c)
        temp_lis.append(f)
        bd.DrawPoints(temp_lis)
    

    return c4d.DRAWRESULT_OK

why * 20 will work, * 1or 2 not work (c = (pmg * per_pos[i]).GetNormalized() * 20)?

I found a solution in other posts, and this is an video example:

example code:

import c4d

from c4d import bitmaps,gui





class DraggingArea(c4d.gui.GeUserArea):
    def __init__(self):
        self.startx = 0
        self.starty = 0

    def DrawMsg(self, x1, y1, x2, y2, msg):


        # Initializes draw region
        self.OffScreenOn()
        self.SetClippingRegion(x1, y1, x2, y2)
        icon_bmp = bitmaps.InitResourceBitmap(5159)
        icon_clip = bitmaps.GeClipMap()
        icon_clip.InitWithBitmap(icon_bmp,icon_bmp.GetInternalChannel())

        clip = bitmaps.GeClipMap()
        w,h = self.GetWidth(),self.GetHeight()
        clip.Init(w,h)
        clip.BeginDraw()
        clip.SetColor(0,0,180)
        clip.FillRect(0,0,w,int(h*0.4))
        clip.SetColor(180,0,0)
        clip.FillRect(0,int(h*0.4),w,h)

        clip.SetDrawMode(c4d.GE_CM_DRAWMODE_BLEND,255)
        clip.Blit(self.startx,self.starty,icon_clip,0,0,icon_clip.GetBw(),icon_clip.GetBh(),c4d.GE_CM_BLIT_COL)


        clip.EndDraw()
        # Get default Background color
        bmp = clip.GetBitmap()
        self.DrawBitmap(bmp,0,0,w,h,0,0,w,h,c4d.BMP_NORMAL)




    def InputEvent(self, msg):
        """
        Called by Cinema 4D, when there is a user interaction (click) on the GeUserArea.
        This is the place to catch and handle drag interaction.

        :param msg: The event container.
        :type msg: c4d.BaseContainer
        :return: True if the event was handled, otherwise False.
        :rtype: bool
        """
        # Do nothing if its not a left mouse click event
        if msg[c4d.BFM_INPUT_DEVICE] != c4d.BFM_INPUT_MOUSE and msg[c4d.BFM_INPUT_CHANNEL] != c4d.BFM_INPUT_MOUSELEFT:
            return True

        # Retrieves the initial position of the click
        mouseX = msg[c4d.BFM_INPUT_X]
        mouseY = msg[c4d.BFM_INPUT_Y]
        mouse_pos_dict = self.Global2Local()
        x, y = mouse_pos_dict['x'] + msg.GetInt32(c4d.BFM_INPUT_X), mouse_pos_dict['y'] + msg.GetInt32(
            c4d.BFM_INPUT_Y)  
        self.startx = x
        self.starty = y

        # Initializes the start of the dragging process (needs to be initialized with the original mouseX, mouseY).
        self.MouseDragStart(c4d.KEY_MLEFT, mouseX, mouseY, c4d.MOUSEDRAGFLAGS_DONTHIDEMOUSE | c4d.MOUSEDRAGFLAGS_NOMOVE)
        isFirstTick = True

        # MouseDrag needs to be called all time to update information about the current drag process.
        # This allow to catch when the mouse is released and leave the infinite loop.
        while True:

            # Updates the current mouse information
            result, deltaX, deltaY, channels = self.MouseDrag()
            if result != c4d.MOUSEDRAGRESULT_CONTINUE:
                break

            # The first tick is ignored as deltaX/Y include the mouse clicking behavior with a deltaX/Y always equal to 4.0.
            # However it can be useful to do some initialization or even trigger single click event
            if isFirstTick:
                isFirstTick = False
                continue

            # If the mouse didn't move, don't need to do anything
            if deltaX == 0.0 and deltaY == 0.0:
                continue

            # Updates mouse position with the updated delta
            mouseX -= deltaX
            mouseY -= deltaY
            x -= deltaX
            y -= deltaY
            self.startx = int(x)
            self.starty = int(y)




            # Redraw the GeUserArea (it will call DrawMsg)
            self.Redraw()

        # Asks why we leave the while loop
        endState = self.MouseDragEnd()



        return True


class MyDialog(c4d.gui.GeDialog):
    """
    Creates a Dialog with only a GeUserArea within.
    """

    def __init__(self):
        # It's important to stores our Python implementation instance of the GeUserArea in class variable,
        # This way we are sure the GeUserArea instance live as long as the GeDialog.
        self.area = DraggingArea()

    def CreateLayout(self):
        """
        This method is called automatically when Cinema 4D Create the Layout (display) of the Dialog.
        """
        self.AddUserArea(1000, c4d.BFH_SCALEFIT | c4d.BFV_SCALEFIT)
        self.AttachUserArea(self.area, 1000)
        return True


def main():
    # Creates a new dialog
    dialog = MyDialog()

    # Opens it
    dialog.Open(dlgtype=c4d.DLG_TYPE_MODAL_RESIZEABLE, defaultw=500, defaulth=500)


if __name__ == '__main__':
    main()

@gheyret Thanks for your help!
i use "c4d.CallCommand(12147) # Redraw" to replace c4d.EventAdd() or c4d.Redraw(), it also work!

change code:

        if id == 1001:
            for obj in doc.GetObjects():
                obj.ChangeNBit(c4d.NBIT_EHIDE,c4d.NBITCONTROL_CLEAR)
            c4d.CallCommand(12147) # Redraw
            return True

@r_gigante @zipit
The detailed explanation is shown below
“up interpolattion”


Try use "spline trail"

I read some papers, but always been very slow, just only expanded know, such as Frenet–Serret formulas etc. But I did not directly find a better way to replace my current method, and I have been looking for it.

Computation of Rotation Minimizing Frames This seems to be a good paper, I will read it carefully.

@m_adam Thank you for your team's reply.
I will share my exploration in this post in the future.

The problem has been resolved, reinstall the graphics driver and perform a custom clean installation！

try use GetDirty(DIRTYFLAGS_CACHE)，compare last dirty and current dirty

@i_mazlov Thank you for your detailed reply, it was really helpful！
The following video shows the results, which work well. The blue polygon uses GetPolyPointST()

Hi,
you can read this thread

Hi @i_mazlov
Through exploring these two pages，page1,page2, I have converted them into Python code Inverse_Bilinear_Interpolation(), which can replace GetPolyPointST(). I am not sure why GetPolyPointST() may obtain incorrect values in certain situations, but Inverse_Bilinear_Interpolation() does not go wrong in complex situations.

video use Inverse_Bilinear_Interpolation()

code:

import math


# algorithm_InverseBilinearInterpolation 逆双线性插值 的算法

def Wedge2D(v:c4d.Vector,w:c4d.Vector):
    return v[0] * w[1] - v[1] * w[0]

def Inverse_Bilinear_Interpolation(p:c4d.Vector,p0:c4d.Vector,p1:c4d.Vector,p3:c4d.Vector,p2:c4d.Vector):

    """
    注意对点顺序的定义
    Attention :  points Order

    p2 --- p3
    |      |
    |      |
    p0 --- p1

    """

    q = p - p0
    b1 = p1 - p0
    b2 = p2 - p0
    b3 = p0 - p1 - p2 + p3

    A = Wedge2D(b2,b3)
    B = Wedge2D(b3,q) - Wedge2D(b1,b2)
    C = Wedge2D(b1,q)
    # 求V - solve v
    if abs(A) < 0.00000001:
        v = -C / B
    else:
        discrim = B * B - 4.0 * A * C
        v = 0.5 * (-B - math.sqrt(discrim)) / A  # CCW
        #v = 0.5 * (-B + math.sqrt(discrim)) / A  # CW

    # 求 u - solve u
    denom = b1 + v * b3

    if abs(denom[0]) > abs(denom[1]):
        u = (q[0] - b2[0] * v) / denom[0]
    else:
        u = (q[1] - b2[1] * v) / denom[1]

    return u,v
# example use CPolygon point position a,b,c,d, and point p in quard(CPolygon)
# u,v = Inverse_Bilinear_Interpolation(p,a,b,c,d)

sample file: custom-quadrilateral.c4d

But for the code part, there are still some doubts about the difference between CCW and CW. When I understand what's going on, I will come back and reply. If any friend can explain, that's the best!

When I restart C4D, I cannot reproduce this problem. It's really confusing, c4d 2025.2.1 (And I also forgot to save the file at that time, resulting in the loss of the file on site)

hi,
A parent object has 2 child objects whose global matrix are the same. They have the same frozen transform value, but the transform values are different. I used GetFrozenMln() to obtain the frozen matrix and found that the frozen matrix of the 2 child objects are *different.

Why do 2 child objects have the same frozen transform value but different frozen matrix?

@i_mazlov there is video, 2025.2.1,win11

Hi,
use bellow code will causing C4D to crash

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:
    rd = c4d.documents.RenderData()
    rd[c4d.RDATA_FRAMERATE] = 2.0


if __name__ == '__main__':
    main()

safe setting code:

    rd = c4d.documents.RenderData()
    data = rd.GetDataInstance()
    data[c4d.c4d.RDATA_FRAMERATE] = 2.0

bug?

@i_mazlov Thanks,it works!

@i_mazlov Thanks

@i_mazlov Thanks,in my code I found an error and directly used the value obtained from PRIORITYVALUEMYODE in the priority GUI to set the list The priority parameter in Add() is a low-level error.
But there is still a problem. When I used your code and adjusted the priority of **Python tag*to expression 1, the calculation order did not execute as expected. Where exactly is the problem？
My version is also 2025.2.0

@i_mazlov Thanks for reply!
I added this flag and modified the content of AddToExecution(). Execute() was successfully called, but it did not run in the expected calculation order. In the image below, The Cube object has a Python tag with priority=expression 0 and objectplugin with priority=expression 10. My expected work order should be python tag (priority=expression 0) -> objectplugin (priority=expression 10), but why is the actual running result objectplugin (priority=expression 10) ->python tags (priority=expression 10)

my code:

    def Execute(self, op, doc, bt, priority, flags) -> int:

        print("Execute")
        return c4d.EXECUTIONRESULT_OK

    def AddToExecution(self, op, list) -> bool:
        print("AddToExecution")
        mode = op[c4d.S_TEMP_PRIORITY].GetPriorityValue(c4d.PRIORITYVALUE_MODE)
        list.Add(op, mode,c4d.EXECUTIONFLAGS_NONE)

Hi,
In the tag plugin, i use MSG_EDIT in Message() to detect the double-click behavior of the mouse, and then execute some commands. However, when create tag, MSG_EDIT is also used. I tried using gui.GetInputState (c4d.BFM_INPUT_MOUSE, c4d.BFM_INPUT_DOUBLECLICK,bc) obtains specific information to distinguish between label create tag and double-click behavior, but bc no double click information is obtained.
code:

    def Message(self, node: GeListNode, type: int, data: object) -> bool:
        if type == c4d.MSG_EDIT:
            
            c4d.CallCommand(200000084) # Rectangle Selection

            bc = c4d.BaseContainer()
            gui.GetInputState(c4d.BFM_INPUT_MOUSE,c4d.BFM_INPUT_DOUBLECLICK,bc)
            if bc[c4d.BFM_INPUT_DOUBLECLICK] : 
                print("double")
            return True
        return True

How to distinguish between these two behaviors
Thanks for any help!

Hi,
I have created a object modifier plugin and I want it to work once in priority Expression 10, and then again in Generator 1. How can I make it work as expected?
In the code, AddToExecution() and Execute() do not seem to work (the documentation states that switching priorities requires calling these two functions).

import c4d
from c4d import plugins, bitmaps


PLUGIN_ID = 1000001

class S_Temp(plugins.ObjectData):


    def Execute(self, op, doc, bt, priority, flags) -> int:
        print("Execute")
        return c4d.EXECUTIONRESULT_OK

    def AddToExecution(self, op, list) -> bool:
        print("AddToExecution")
        return True


    def Init(self, node, isCloneInit: bool) -> bool:
        self.InitAttr(node, c4d.BaseList2D, c4d.S_TEMP_POSEDTARGETS)
        self.InitAttr(node, c4d.BaseList2D, c4d.S_TEMP_POSEDSOURCEADD)
        self.InitAttr(node, c4d.PriorityData, c4d.S_TEMP_PRIORITY)

        if not isCloneInit:
            pridata = c4d.PriorityData()
            pridata.SetPriorityValue(c4d.PRIORITYVALUE_MODE, c4d.CYCLE_EXPRESSION)
            pridata.SetPriorityValue(c4d.PRIORITYVALUE_PRIORITY, 10)
            node[c4d.S_TEMP_PRIORITY] = pridata
        return True

    def ModifyObject(self, mod, doc, op, op_mg, mod_mg, lod, flags, thread):
        allp = [pos + c4d.Vector(0,100,0) for pos in op.GetAllPoints()]
        op.SetAllPoints(allp)
        op.Message(c4d.MSG_UPDATE)

        return True


if __name__ == '__main__':
    plugins.RegisterObjectPlugin(id=PLUGIN_ID, str="S_Temp", g=S_Temp, description="stemp", info=c4d.OBJECT_MODIFIER,
                                 icon=None)

Here is the file of this plugin --> s_Temp.zip

Thanks for any help!