Noob question - referencing object

Helper

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On 04/12/2012 at 07:26, xxxxxxxx wrote:

From where do you want to reference the object? You can usually just store the object reference somewhere (global scope, instance attribute, dictionary, list, whatever)

-Nik

Helper

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On 04/12/2012 at 07:45, xxxxxxxx wrote:

Thanks Niklas, but storing the reference is not my challenge. I just don't know where to find the unique identifier, assuming I have several of the same object type. I could put it in the global scope though once I get it.

Helper

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On 04/12/2012 at 08:17, xxxxxxxx wrote:

There is no identifier for objects in C4D that always stays attached to the object.
Maxon wants us to keep track of objects by searching for them periodically as needed.
I think the reasoning for this is because objects often get destroyed and rebuilt using a copy of itself. Thus destroying any hard coded ID# it might have had.

However...I do have my own little trick(hack) that I've used to give an object a hard coded ID#:

    #This will assign an ID# to your object  
  #To avoid clashing with the ID#'s in C4D...I use negative numbers for this  
  obj = doc.SearchObject("Cube")  
  obj.SetUniqueIP(-55)  
  
  
  #Now that the object has an ID# I can use it as a condition to grab that object  
  first = doc.GetFirstObject()  
  GetIp = first.GetUniqueIP()  
  if GetIp == -55: first.SetBit(c4d.BIT_ACTIVE)  #Only selects the first object if it has IP# -55  
  c4d.EventAdd()

I suppose you could do the same thing with a BaseContainer too.

It's not something I would use very often. Since the ID will break when the objects changes in certain cases.
But if you have an object that doesn't change. And you just want a way to reference it. This might be an option.

-ScottA

Helper

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On 04/12/2012 at 08:36, xxxxxxxx wrote:

Thanks Scott.
Yes, I've been searching for the objects in the same way. But not assigning the IP like you had. I was looking at that property, but wasn't sure why I would ever need it
Guess I'll take a harder look at that one. Thanks again.

Jim

Helper

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On 04/12/2012 at 09:30, xxxxxxxx wrote:

I'm not sure why you should not be able to store the reference but need to search for it via it's IP?

-Nik

Helper

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On 04/12/2012 at 11:55, xxxxxxxx wrote:

My concern is that if the end user decides to change the object name I wouldn't want things to break. If I could listen to whether the name is changed, I could reset the reference based on the SearchObject('foo'), but I don't know how to check for any name change. Still learning the SDK.

Helper

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On 04/12/2012 at 12:21, xxxxxxxx wrote:

ids or naming conventions for object identfication can be used for testing purposes at best. use

the pointer approach on objects c4d offers. the GUI front-ends for this would be the LinkBox gui
and the InExcludeData gui, which both take BaseList2D as inputs.
this will allow you to perform any modification on the objects, including their names, without losing
the access to these objects.

that little id trick scott showed you there shouldn't be treated as exemplary (no offense). also the
BaseDocument.SearchObject()method isn't meant to be used on a large scale. on a script/ non gui
basis you either loop through all objects and check their attributes/type for identification or you
simply use c4ds selections (c4d.document.BaseDocument).

Helper

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On 04/12/2012 at 13:52, xxxxxxxx wrote:

Ferdinand,
The LinkBox, yes, I understand - thank you.

For the looping through all objects, would I check for the name attribute if I'm making a replicator that has an incremental naming system? Or is there another attribute that I would check in order to perform operations on each item individually?

As I have it, I am replicating a null with nested objects. Each new object is named with an incremental number suffix (_0 to _n). I can also remove some or add more. I am also performing both identical and unique operations on each replicant as well. Therefore I have been looping and using the .SearchObject method.

Again, I am just learning the C4d SDK.

I welcome your thoughts and opinions, as I work through this.

I appreciate it.
Thank you,

Jim

Helper

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On 04/12/2012 at 15:31, xxxxxxxx wrote:

Originally posted by xxxxxxxx

For the looping through all objects, would I check for the name attribute if I'm making a replicator that has an incremental naming system?

i meant more a property / type driven selection. the most basic element of all c4d objects,
the c4d.Atom, provides a GetType() / CheckType() method with which you could make some
basic decisons. Is a material, is it a shader, is polygon object or is a MoGraph Shader Effector ?

if (myObject.GetType() == c4d.Onull) :
	doSomething()

on the other hand there are the properties of the object (the settings shown in the attribute
manager) which you access with the bracket syntax. this goes down to the the c4d.BaseContainer
and c4d.DescID system.

while (myObject[myBooleanProperty]) :

On your specific task - it is quite difficult to understand what you want to achieve (at least for me),
it sounds a bit like some rigging stuff. however, using object names as object identificator is really
unsafe and should be avoided at all cost. for massive object references use InExcludeData which is
named a bit misleading, because it is just a list of object (GeListNode) links.

if this all doesn't help, please tell us more precisely what you want to do and where the objects
are coming from. when you import some super massive rig from somewhere the user will have to
do some mapping (LinkBox) or you will have to rely un propper naming. when you create the
objects yourself just use some form reference as nikklas wrote.

last but not least some very basic but commented example:

import c4d
  
def main() : 
    # a list to store our objects   
    myObjectList = []
    
    # create some objeccts
    for n in range(10) :
        # a parametric cube
        myCube = c4d.BaseObject(c4d.Ocube)
        # a display tag
        myTag = c4d.BaseTag(c4d.Tdisplay)
        # attach the tag to the cube
        myCube.InsertTag(myTag)
        
        # add both to a local list
        myObjectList.append(myCube)
        myObjectList.append(myTag)
        
        # insert cube with the tag into the document
        doc.InsertObject(myCube)
        
    # update the gui, the objects are now in the document  
    c4d.EventAdd()
    
    # from somewehre else we want to access our objects and we have 
    # this list, but we do not know that it contains cube and display tags in a
    # alternating order, we only know it is a list of c4d.Atoms ,which might also
    # contain other stuff. so we loop through it and check every object.
    
    # some initial vector for the cube size
    size = c4d.Vector (25,25,25)
    
    # loop through the data
    for n in myObjectList:
        # if it is a cube set its size and increment the size by factor 1.1
        if (n.GetType() == c4d.Ocube) :
            n[c4d.PRIM_CUBE_LEN] = size
            size *= 1.1
        # if it is a display tag activate the force shading mode and set it to lines
        if (n.GetType() == c4d.Tdisplay) :
            n[c4d.DISPLAYTAG_AFFECT_DISPLAYMODE] = True
            n[c4d.DISPLAYTAG_SDISPLAYMODE] = 6
            
if __name__=='__main__':
    main()

ps : just to be clear, this is a working script example .

Helper

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On 05/12/2012 at 09:21, xxxxxxxx wrote:

Ferdinand,
I see your method and I understand.
Thank you for taking the time to explain so clearly.

Yes, I have seen this approach before, and I think that it's not specific enough for my needs, as I will have multiple deformers that I'll be adjusting dynamically – say a couple arrays of bend deformers that will bend from a low value to a high value based on some condition.

Perhaps once I develop my code to a further point, I will share and hope for feedback on how to improve it, yes? That would be great and helpful.

Thanks again for the time and effort to help me learn.

Jim