Together with the help from the c4dlounge.eu forum the issues is solved.
The main issue was I did not read the manual good enough.

"Note that Size symbolizes the axis size and not the expansion of the object itself. For planar projections, the true dimension is the two/fold of the axis length."

I did some more testing and I think I got it now.
In MouseInput() get and set your coordinates.
Then call c4d.DrawViews(). This will call Draw(), where you can (and should) do the drawing like bd.DrawLine2D().

class PlaceTool(c4d.plugins.ToolData):       	

    v1 = c4d.Vector(0,0,0)
    v2 = c4d.Vector(0,0,0)
    
    def Draw(self, doc, data, bd, bh, bt, flags):	
        bd.SetPen(c4d.Vector(256,256,256))
        bd.DrawLine2D(self.v1, self.v2)
        return True
        
    def MouseInput(self, doc, data, bd, win, msg):
        self.v1 = c4d.Vector(0,0,0)
        self.v2 = c4d.Vector(msg[c4d.BFM_INPUT_X], msg[c4d.BFM_INPUT_Y], 0)
        c4d.DrawViews(c4d.DRAWFLAGS_ONLY_ACTIVE_VIEW|c4d.DRAWFLAGS_NO_THREAD|c4d.DRAWFLAGS_NO_REDUCTION|c4d.DRAWFLAGS_STATICBREAK)  #Added 
        return True
        
        

Thanks, great explanation!
One small issue. Delete doesn't work because objParent' is not defined.

Traceback (most recent call last):
File "scriptmanager", line 251, in DeletePressed
NameError: global name 'objParent' is not defined

Here the code that, I think, solves the issue:

    def DeletePressed(self, root, userdata):
        "Called when a delete event is received."
        for tex in reversed(list(TextureObjectIterator(self.listOfTexture))):
            if tex.IsSelected:
                objParent = tex.GetParent()               # Added
                listToRemove = objParent.GetChildren() if objParent is not None else self.listOfTexture
                listToRemove.remove(tex)

@heilei said in Best plugin type for background (thread) processing?:

Py-TextureBaker

That is a very good working example.
I rebuild my plugin using py-texturebaker and now it is working!

After some studying, I think @PluginStudent is fully correct when referring to the global scope.

@PluginStudent said in Best plugin type for background (thread) processing?:

Please read my post above and the C4DThread Manual carefully.

You can start the thread in a CommandData plugin. But this plugin must not own the thread instance. The thread instance should be stored in the global scope.

In the MessageData plugin, you should react to a core message sent from the thread. Nothing else; no creation or waiting.

I guess it is working because in the dialog the thread class is initiated.
textureBakerThread = None
and further in the code it is referenced with self.textureBakerThread.

I was using

        thread = UserThread()
        thread.Start()

Everybody thanks for all the help.

@PluginStudent said in Reading script file into memory:

You have to define the APIS in the projectdefinition.txt of your plugin.

Not in the projectdefinition.txt of the solution.

Great, tht solved it. Thanks!

To summarise, there are 2 projectdefinition.txt files.

1. on main / sdk level, Define which project (plugins, etc.)
   Example:

Platform=Win64;OSX
Type=Solution
 
// defines the level of rigour of the source processor's style check
stylecheck.level=0

Solution=\
	plugins/cinema4dsdk;\
	plugins/maxonsdk.module;\
	plugins/commandline;\
    plugins/CommandLineRendering

2. on plugin level, // Configuration of a custom solution in the projectdefinition.txt file
   Example:

// Supported platforms
Platform=Win64;OSX

// Type of project
Type=DLL

// this plugin depends on these frameworks:
APIS=\
  cinema.framework; \
  misc.framework; \
  image.framework; \
  core.framework; \
  python.framework

// Enable some advanced classic API support; not needed for hybrid plugins
C4D=true

// Plug-in code-style check level
stylecheck.level=0

// Custom ID
ModuleId=net.maxonexample.commandlinerender

Yes, I am referring to that page.
I saw that statement, but I assumed it was the main definition for the python plugin.

  // set __name__ = __main__
  scope.Add("__name__"_s, maxon::Data("__main__"_s)) iferr_return;

If I understand you correctly, I can add different parameters with different values.
For example:

  // set __param1__ = "c:/temp"
  scope.Add("param1"_s, maxon::Data("c:/temp"_s)) iferr_return;
  scope.Add("param2"_s, maxon::Data(220)) iferr_return;

Yes, I must read the manuals more throroughly (RTFMS).
Excuses: it is so much and I just wanted to compiler R20 in R21.
But you are correct.

BUT, adding iferr to the code worked, AND also solved the other issue.
Everything is working now!

Thanks!

Great input, thanks.
I will have a look at the Mac mini, if not, I will go back to a windows desktop.
Again, thank you both.

Regards,
pim

I am looking for a new pc with windows 11.
This time I would like to buy a mini pc.
However, most mini pc have none NVidia card, for example the AMD Ryzen 680M 12 Core 2400 MHz graphic card.
Is that a good choice for running cinema 4d?

Ok, I understand it now better, thanks.

@pim
I solved it.
You must insert the shader into the document and then insert it in the displacer

from typing import Optional
import c4d

doc: c4d.documents.BaseDocument  # The active document
op: Optional[c4d.BaseObject]  # The active object, None if unselected

def main() -> None:

    displacer = c4d.BaseObject(c4d.Odisplacer)
    doc.InsertObject(displacer)
    
    shd = c4d.BaseList2D(c4d.Xnoise)
    doc.InsertShader(shd)
    displacer[c4d.ID_MG_SHADER_SHADER] = shd
    
    #displacer.InsertShader(shd)
    c4d.EventAdd()
    
if __name__ == '__main__':
    main()

I am trying to set the Shader field in the Displacemtn object to Noise. However, the filed is not filled.

Here the code.
What am I doing wrong?

from typing import Optional
import c4d

doc: c4d.documents.BaseDocument  # The active document
op: Optional[c4d.BaseObject]  # The active object, None if unselected

def main() -> None:

    displacer = c4d.BaseObject(c4d.Odisplacer)
    doc.InsertObject(displacer)
    
    shd = c4d.BaseList2D(c4d.Xnoise)
    #displacer[c4d.ID_MG_SHADER_SHADER] = shd
    
    displacer.InsertShader(shd)
    c4d.EventAdd()
    
if __name__ == '__main__':
    main()
    

Thanks again for the great explanation.
I guess I will go for a different workflow then.

I am not sure what you mean with a Baselink?

A Cloner, imo, does not notice when a child is added or deleted.

I guess there is (somewhere) a message that signals a deletion?

I have a plugin that created a Cloner and insert planes as children of that cloner. After that I update the Cloner Count.
However, when the user deletes a plane ( a child of that cloner), the Cloner count must be updated.

What is the best way to detect an object has been deleted and I can update the Cloner count?

I really do appreciate all your effort and I will take your warning seriously and create my own menu Tab.
Thanks again.

Regards,
Pim

@ferdinand
I run the script, but it hangs cinema 4d.
After some debugging, I could see that the insertion point was found and that it was inserted in items.
I am not sure what statement hangs cinema 4d.

I am using R2023.2.1 on a Windows 10 Pro 22H2.