SOLVED Parameter Description Access not working as expected

I am working on limited C4D python api understanding, so forgive what may be an noob question.

I am building a specialized script for my personal workflow to extract parameter data from a project build. The goal being that it loops through all the scene objects, tags, and parameters, then checks if parameter is not default (or has been changed), then returns a tab delimited string consisting of Object name / Parameter name / Parameter Value

The resulting list I like to use as a notes reference for when I make my video tutorials. It helps me remember what I changed to achieve final result. So only the changed parameters are required.

Currently I have the Object/parameter loop, name & value retrieval functioning by cobbling together some snippets I've found online, and from my own knowledge. Some checks and adjustments made to results along the way as well. What I am having issues with are the parameter description name attributes located in this list: https://developers.maxon.net/docs/Cinema4DPythonSDK/html/modules/c4d/Description/index.html#c4d.Description

So far I have tried using changed and default to check parameter, but both fail and return None instead of True/False I assume I am using them improperly or there may be a limitation to how I want to use them. As I read in the help docs (url above), changed returns bool if entry is changed, and default returns the parameter default value. Changed would be an easier use, but if I have to do a...

default != "value"

...kind of check, that's ok too.

c4d.DESC_CHANGED
c4d.DESC_DEFAULT

Any insight as to how I can check for a parameter that in not default or has changed would be appreciated.

This is the code I have so far, and I am aware that some parameters that are Gradients, Time, Custom, etc.. are not handled with this code currently. Next hurdle to cross when I get to that though.

import c4d
from c4d import gui

# Main function
def main():
    o = op
    if o is not None:
        recurse(o)


def recurse(o):
    obj = o
    if obj is not None:
        #Misc variables
        tab = "\t"
        
        #Header
        print "Name\tParameter\tValue\tParam ID"

        #Print object name
        on = obj.GetName()
        print on

        #Print object PSR
        print on + "\t" + "Position\t" + str(obj[c4d.ID_BASEOBJECT_REL_POSITION])
        print on + "\t" + "Scale\t" + str(obj[c4d.ID_BASEOBJECT_REL_SCALE])
        print on + "\t" + "Rotation\t" + str(obj[c4d.ID_BASEOBJECT_REL_ROTATION])
        print on + "\t" + "Vis Editor\t" + str(obj[c4d.ID_BASEOBJECT_VISIBILITY_EDITOR])
        print on + "\t" + "Vis Renderer\t" + str(obj[c4d.ID_BASEOBJECT_VISIBILITY_RENDER])
        
        #Display color check/conversion and print
        uc = obj[c4d.ID_BASEOBJECT_USECOLOR]
        if uc == 2:
            dc = obj[c4d.ID_BASEOBJECT_COLOR]
            print on + "\t" + "Display Color\tVector(" + str(dc[0]*255) + ", " + str(dc[1]*255) + ", " + str(dc[2]*255) + ")"
        
        #Get object data
        data = obj.GetData()

        #Get object description
        description = obj.GetDescription(c4d.DESCFLAGS_DESC_0)
        for bc, paramid, groupid in description:
            #Process object parameters
            isgroup = paramid[0].dtype==c4d.DTYPE_GROUP
            if isgroup:
                continue

            group = groupid[0].id
            filtergroup = group!=c4d.Tbaselist2d and group!=c4d.FALLOFF_GROUPFALLOFF
            idname = bc[c4d.DESC_IDENT]

            if idname:
                filtergroup = filtergroup and not idname.startswith("ID_BASEOBJECT")

            if filtergroup:
                if bc[c4d.DESC_NAME] and bc[c4d.DESC_IDENT]:
                    #-------------------------------------------
                    #ATTEMPTS TO CHECK FOR PARAMETER CHANGED OR DEFAULT
                    #-------------------------------------------
                    #Fails to return changed correctly
                    #if bc[c4d.DESC_CHANGED] == 1:
                    #Fails to return default correctly
                    #if bc[c4d.DESC_DEFAULT] == 1:
                    #-------------------------------------------
                    try:
                        #Adjust color float to 255 range
                        vec = obj[paramid]
                        if "Color" in bc[c4d.DESC_NAME] and "Vector" in str(vec):
                            vec = obj[paramid]
                            val = "Vector(" + str(vec[0]*255) + ", " + str(vec[1]*255) + ", " + str(vec[2]*255) + ")"
                        else:
                            val = str(obj[paramid])
                        print on + "\t" + bc[c4d.DESC_NAME] + "\t" + val
                    except:
                        print on + "\t" + bc[c4d.DESC_NAME] + ": PARAMETER REQUIRES MANUAL EXTRACTION"

        #Get object tags
        tags = obj.GetTags()
        for t in tags:
            tn = t.GetTypeName()
            if tn is not "" or None:
                #Add spacer in output
                print ""
                
                #Get tag name
                print t.GetTypeName()
                try:
                    #Process tag parameters
                    tdesc = t.GetDescription(c4d.DESCFLAGS_DESC_0)
                    for bc, paramid, groupid in tdesc:
                        #-------------------------------------------
                        #ATTEMPTS TO CHECK FOR PARAMETER CHANGED OR DEFAULT
                        #-------------------------------------------
                        #Fails to return changed correctly
                        #if tn[c4d.DESC_CHANGED] == 1:
                        #Fails to return default correctly
                        #if tn[c4d.DESC_DEFAULT] == 1:
                        #-------------------------------------------
                        isgroup = paramid[0].dtype==c4d.DTYPE_GROUP
                        if isgroup:
                            continue
    
                        group = groupid[0].id
                        filtergroup = group!=c4d.Tbaselist2d and group!=c4d.FALLOFF_GROUPFALLOFF
                        idname = bc[c4d.DESC_IDENT]
    
                        if idname:
                            filtergroup = filtergroup and not idname.startswith("ID_BASEOBJECT")
    
                        if filtergroup:
                            if bc[c4d.DESC_NAME] and bc[c4d.DESC_IDENT]:
                                try:
                                    #val = tn+"[c4d."+str(idname)+"]"
                                    print tn + "\t" + bc[c4d.DESC_NAME] + "\t" + str(t[paramid])
                                except:
                                    print tn + "\t" + bc[c4d.DESC_NAME] + ": PARAMETER REQUIRES MANUAL EXTRACTION"

                except:
                    print "--UNKNOWN PARAMETER--"


        #Check for child object
        d = obj.GetDown()
        if d is not None:
            recurse(d)

        #Get next object
        n = obj.GetNext()
        if n is not None:
            recurse(n)
    else:
        print "Error: Select one starting object first."

# Execute main()
if __name__=='__main__':
    main()

Hi @davidtorno sorry I overlooked the version in the post tag.
You are right ID_BASELIST_ICON_COLOR was added in R21. So you could remove it.

Regarding the second issue, you are also right, a PolygonObject/SplineObject have no history at all, so you can't trace them, even modeling operation done on them can't be retrieved at least by the way I propose.
You could do a SceneHook(only available in C++) to monitor the change made by a tool by listening to EVMSG_CHANGE (triggered when a EventAdd is processed) figured out if a polygon object changed (by iterating over each scene object, and checking their dirty bits), then retrieve the current tool and parameters, but as you can see it's a pretty complex task.

So in your case I would suggest to simply ignore edited object (so PolygonObject and SplineObject) by editing ignoredObjs variable like so

ignoredObjs = [c4d.Opolygon, c4d.Opoint, c4d.Ospline, c4d.Oline]

Cheers,
Maxime.

Hi,

welcome to the forum. If I understand your posting correctly, your question is how to test if a description parameter has been modified in respect to its default value. Your code is almost there, but you probably misconstrued c4d.DESC_DEFAULT as a boolean indicating a changed value, but it is actually the actual default value. So to test if the parameter has been modified, it would be something like this:

description = node.GetDescription(c4d.DESCFLAGS_DESC_0)
for bc, descid, _ in description:
    # Test if the current value is identical to the default value.
    is_default = bc[c4d.DESC_DEFAULT] == node[descid]

Cheers,
zipit

@zipit said in [python] Parameter Description Access not working as expected:

Your code is almost there, but you probably misconstrued c4d.DESC_DEFAULT as a boolean indicating a changed value, but it is actually the actual default value.

Correct, I understood it as indicating a changed value. Good to know. These are the nuances I am still adjusting to with C4D python. Thanks for the answer and explanation. I will give this a go tomorrow when I’m back on my machine. I appreciate your help.

Hi,

after reading your reply I realised, that I probably should have also mentioned that Cinema has a dirty system, which will let you check if an object has been modified. It is scattered over multiple classes, but most of it is attached to C4DAtom, with the major method being C4DAtom.GetDirty.

Cheers,
zipit

@zipit So I have tried implementing your check for DESC_DEFAULT and I am still not getting values for default.

#.....Snippet from my script, full code at bottom of post.
        #Process tag parameters
        desc = o.GetDescription(c4d.DESCFLAGS_DESC_0)
        for bc, paramid, groupid in desc:
            
            #Check if current value matches default value
            is_default = bc[c4d.DESC_DEFAULT] == o[paramid]
            
            #print both values for visual comparison
            print "DEBUG:: " + str(bc[c4d.DESC_DEFAULT]) + " == " + str(o[paramid]) + " --> " + str(is_default)
            
            if is_default is not True:
#.....

As an example I am currently using a simple Null object for testing the default functionality. Changing only the Object > Display parameter to see if my code catches if it is set to default or not. The print output is like this so far. For simplicity I've only posted the Object Properties results.

Object Properties
DEBUG:: None == 0 --> False
	Display	0
DEBUG:: None == 10.0 --> False
	Radius	10.0
DEBUG:: None == 10.0 --> False
	Aspect Ratio	10.0
DEBUG:: None == 0 --> False
	Orientation	0

I would expect this debug result to read as this since all parameters are at their defaults.

Object Properties
DEBUG:: 0 == 0 --> True
DEBUG:: 10.0 == 10.0 --> True
DEBUG:: 10.0 == 10.0 --> True
DEBUG:: 0 == 0 --> True
#...

...but bc[c4d.DESC_DEFAULT] is continuously returning None for some reason. What am I missing here? Thanks again for any assistance on this.

Here is my full script code currently. I cleaned up a lot from previous build as it was getting very messy. The param name/value retrieval is now it's own function (def):

import c4d
from c4d import gui

# Main function
def main():
    o = op
    if o is not None:
        recurse(o)

def getParamData(o):
    try:
        #misc var
        grpName = ""
        
        #Process tag parameters
        desc = o.GetDescription(c4d.DESCFLAGS_DESC_0)
        for bc, paramid, groupid in desc:
            
            #Check if current value matches default value
            is_default = bc[c4d.DESC_DEFAULT] == o[paramid]
            
            #print both values for visual comparison
            print "DEBUG:: " + str(bc[c4d.DESC_DEFAULT]) + " == " + str(o[paramid]) + " --> " + str(is_default)
            
            if is_default is not True:
                isgroup = paramid[0].dtype==c4d.DTYPE_GROUP
                if isgroup:
                    #handle blank names
                    if bc[c4d.DESC_NAME] is not "":
                        grpName = bc[c4d.DESC_NAME]
                        print grpName
        
                #check for param name and ident
                if bc[c4d.DESC_NAME] and bc[c4d.DESC_IDENT]:
                    try:
                        #Adjust color float to 255 range
                        vec = o[paramid]
                        if "Color" in bc[c4d.DESC_NAME] and "Vector" in str(vec):
                            vec = o[paramid]
                            val = "Vector(" + str(vec[0]*255) + ", " + str(vec[1]*255) + ", " + str(vec[2]*255) + ")"
                        else:
                            #Strip None values out
                            blank = o[paramid]
                            if blank == None:
                                val = ""
                            else:
                                val = str(o[paramid])
                        
                        #handle group name duplicates in results
                        if bc[c4d.DESC_NAME] == grpName:
                            pass
                        else:
                            print "\t" + bc[c4d.DESC_NAME] + "\t" + val
                    except:
                        print "\t" + bc[c4d.DESC_NAME] + ": PARAMETER REQUIRES MANUAL EXTRACTION"
    
    except:
        print "--UNKNOWN PARAMETER--"


def recurse(o):
    obj = o
    if obj is not None:
        #Misc variables
        tab = "\t"

        #Header
        print "Name\tParameter\tValue\tParam ID"

        #Print object name
        on = obj.GetName()
        print on

        #Get object data
        #data = obj.GetData()

        #Get param name and value
        getParamData(obj)

        #Get object tags
        tags = obj.GetTags()
        
        #Loop tags
        for t in tags:
            tn = t.GetTypeName()
            if tn is not "" or None:
                #Add spacer in output
                print ""

                #Get tag name
                print t.GetTypeName()
                
                #Get param name and value
                getParamData(t)


        #Check for child object
        d = obj.GetDown()
        if d is not None:
            recurse(d)

        #Get next object
        n = obj.GetNext()
        if n is not None:
            recurse(n)
    else:
        print "Error: Select one starting object first."

# Execute main()
if __name__=='__main__':
    main()

Hi,

the problem you are running into, is that the default value is an optional description element flag. If no such flag has been provided by the author who wrote the description markup, the element will fall back to the internal default value of that type (e.g. 0 for an integer). This value however won't be reflected in the DESC_DEFAULT field of a Description object, it will return None in this case, like you experienced it in your tests.

You would have to either handle that case manually or use the dirty checksums that I did mention. The problem there is that you can test the data container of a node for being dirty, i.e. its parameters, and by that detect if a parameter has been modified, but not exactly which one of the parameters has been modified.

Cheers,
zipit

@zipit said in Parameter Description Access not working as expected:

You would have to either handle that case manually or use the dirty checksums that I did mention. The problem there is that you can test the data container of a node for being dirty, i.e. its parameters, and by that detect if a parameter has been modified, but not exactly which one of the parameters has been modified.

Hmmm, bummer. Ya the whole goal was to only return parameters not at default value. I've made similar scripts for Houdini, and After Effects. Cinema4D was my last holdout. 🙂

I'll take a look at the dirty checksums. If I can at least tell if something was changed, it's better than nothing I guess.

Thanks again for the help.

Still far from being fully fleshed out, but could prove helpful to others in some form possibly. It's totally specific to my needs so I make no claims of it's longevity, stability, or usability for anyone else's needs. 🙂

The script prints to the console a tab delimited list of all project objects beginning with a selected object. It then loops downwards through all objects, object parameters, tags, and tag parameters gathering names & values. Choose top most object in your project to get all items in your project.

Here's the code I'm settling on for the moment. I did a few common parameter conversions from numerical value to it's string value seen in the UI.

Example 1: Toggle switches return "Unchecked" / "Checked" instead or 0 / 1
Example 2: Visible in Editor / Renderer return "On" / "Off" / "Default" instead of 0 / 1 / 2

Source code:

#--------------------------------------------------------
#    [IN DEVELOPEMENT AND NOT COMPLETED YET]
#    Project parameter names and values list script
#    9/2020 David Torno
#--------------------------------------------------------

import c4d
from c4d import gui

# Main function
def main():
    o = op
    if o is not None:
        recurse(o)

def getParamData(o):
    try:
        #--------------------------------------------------------
        #    PARAMETER DATATYPE NUMBERS R20 (Likely to change with C4D versions)
        #    1 = Group
        #    8 = Button
        #    12 = String
        #    15 = Dropdown
        #    133 = Object Link
        #    1000481 = Color Gradient
        #    1009290 = InExclude List
        #    400006001 = Toggle
        #--------------------------------------------------------
        
        #misc var
        grpName = ""
        #Rotation Order conversion
        rotOrder = ["XYZ", "XZY", "YXZ", "YZX", "ZXY", "ZYX", "HPB"]
        #Vis in editor/renderer conversion
        visEditRender = ["On", "Off", "Default"]
        #Toggle conversion
        tog = ["Unchecked", "Checked"]
        
        #Process tag parameters
        desc = o.GetDescription(c4d.DESCFLAGS_DESC_0)
        for bc, paramid, groupid in desc:
            #print str(paramid[0].id), str(paramid[0].dtype), str(paramid[0].creator)
            
            #-------------------------------------------------------
            #Currently checking for default parameter value does not work
            #-------------------------------------------------------
            #Check if current value matches default value
            #is_default = bc[c4d.DESC_DEFAULT] == o[paramid]
            #print both values for visual comparison
            #print "DEBUG:: " + str(bc[c4d.DESC_DEFAULT]) + " == " + str(o[paramid]) + " --> " + str(is_default)
            #if is_default is not True:
            #-------------------------------------------------------
            
            isgroup = paramid[0].dtype==c4d.DTYPE_GROUP
            if isgroup:
                #handle blank names
                if bc[c4d.DESC_NAME] is not "":
                    grpName = bc[c4d.DESC_NAME]
                    print "\t" + grpName
    
            #check for param name and ident
            if bc[c4d.DESC_NAME] and bc[c4d.DESC_IDENT]:
                try:
                    #Adjust color float to 255 range
                    vec = o[paramid]
                    if "Color" in bc[c4d.DESC_NAME] and "Vector" in str(vec):
                        vec = o[paramid]
                        val = "Vector(" + str(vec[0]*255) + ", " + str(vec[1]*255) + ", " + str(vec[2]*255) + ")"
                    else:
                        blank = o[paramid]
                        if blank == None:
                            val = ""
                        else:
                            val = str(o[paramid])
                            
                    #Convert toggle value to name str
                    if str(paramid[0].dtype) == "400006001":
                        val = tog[o[paramid]]
                    
                    #Convert dropdown value to name str
                    if str(paramid[0].dtype) == "15":
                        if "Visible in " in bc[c4d.DESC_NAME]:
                            val = visEditRender[o[paramid]]
                        elif "Rotation Order" == bc[c4d.DESC_NAME]:
                            val = rotOrder[o[paramid]]

                    
                    #handle group name duplicates in results
                    if bc[c4d.DESC_NAME] == grpName or paramid[0].dtype == 8:
                        pass
                    else:
                        print "\t\t" + bc[c4d.DESC_NAME] + "\t" + val
                        
                        #--------------------------------------------------------------------
                        #DEBUG print reveals parameter data type enumeration
                        #--------------------------------------------------------------------
                        #print "DTYPE:" + str(paramid[0].dtype) + "\t\t" + bc[c4d.DESC_NAME] + "\t" + val
                except:
                    print "\t\t" + bc[c4d.DESC_NAME] + ": PARAMETER REQUIRES MANUAL EXTRACTION"
                    
                    #--------------------------------------------------------------------
                    #DEBUG print reveals parameter data type enumeration
                    #--------------------------------------------------------------------
                    #print "DTYPE:" + str(paramid[0].dtype) + "\t\t" + bc[c4d.DESC_NAME] + ": PARAMETER REQUIRES MANUAL EXTRACTION"
    except:
        print "--UNKNOWN PARAMETER--"


def recurse(o):
    obj = o
    if obj is not None:
        #Misc variables
        tab = "\t"

        #Header
        #print "Name\tParameter\tValue\tParam ID"

        #Print object name
        on = obj.GetName()
        print on

        #Get param name and value
        getParamData(obj)

        #Get object tags
        tags = obj.GetTags()
        
        #Loop tags
        for t in tags:
            tn = t.GetTypeName()
            if tn is not "" or None:
                #Add spacer in output
                print ""

                #Get tag name
                print t.GetTypeName()
                
                #Get param name and value
                getParamData(t)


        #Check for child object
        d = obj.GetDown()
        if d is not None:
            recurse(d)

        #Get next object
        n = obj.GetNext()
        if n is not None:
            recurse(n)
    else:
        print "Error: Select one starting object first."

# Execute main()
if __name__=='__main__':
    main()

Example output:

Right fill light
	Basic Properties
		Name	Right fill light
		Layer
		Visible in Editor	Off
		Visible in Renderer	Default
		Use Color	0
		Display Color	Vector(255.0, 255.0, 255.0)
		Enabled	Checked
		X-Ray	Unchecked
		Icon Color	Unchecked
	Coordinates
		Position	Vector(337.76, 0, -211.712)
		Scale	Vector(1, 1, 1)
		Rotation	Vector(1.326, 0, -1.571)
		Rotation Order	HPB
	Quaternion
		Quaternion Rotation	Unchecked
	Freeze Transformation
		Frozen Position	Vector(0, 0, 0)
		Frozen Scale	Vector(1, 1, 1)
		Frozen Rotation	Vector(0, 0, 0)
		Global Position	Vector(337.76, 0, -211.712)
		Global Rotation	Vector(1.326, 0, -1.571)
		Transformed Position	Vector(337.76, 0, -211.712)
		Transformed Scale	Vector(1, 1, 1)
		Transformed Rotation	Vector(1.326, 0, -1.571)
	Object Properties
	General
		Color	Vector(153.765, 216.8775, 229.5)
		Use Temperature	Unchecked
		Color Temperature	6500.0
		Intensity	0.65
		Type	8
		Shadow	2
		Visible Light	0
		No Illumination	Unchecked
		Show Illumination	Checked
		Ambient Illumination	Unchecked
		Show Visible Light	Checked
		Diffuse	Checked
		Show Clipping	Checked
		Specular	Checked
		Separate Pass	Unchecked
		GI Illumination	Checked
		Export to Compositing	Checked
	Details
		Use Inner Value	Checked
		Inner Angle	0.0
		Inner Radius	0.0
		Outer Angle	0.523598775598
		Outer Radius	600.0
		Aspect Ratio	1.0
		Contrast	0.0
		Shadow Caster	Unchecked
		Area Shape	1
		Object
		Size X	1200.0
		Size Y	1200.0
		Size Z	200.0
		Falloff Angle	3.14159265359
		Infinite Angle	0.00872664625997
		Samples	40
		Add Grain (Slow)	Unchecked
		Show in Render	Unchecked
		Show as Solid in Viewport	Unchecked
		Show in Specular	Checked
		Show in Reflection	Unchecked
		Visibility Multiplier	1.0
		Falloff	0
		Falloff Inner Radius	0.0
		Falloff Radius / Decay	500.0
		Colored Edge Falloff	Unchecked
		Z Direction Only	Unchecked
		Use Gradient	Unchecked
		Color	<c4d.Gradient object at 0x000000D7967B9570>
		Use Near Clipping	Unchecked
		Near Clipping from	0.0
		Near Clipping to	10.0
		Use Far Clipping	Unchecked
		Far Clipping from	90.0
		Far Clipping to	100.0

Hi,

thanks for sharing, it is always nice if someone does that. I haven't red all your code and also did not run it, but I think the following points should be made:

# You should not type test like that, because it is bound to go wrong at
# some point.
if "Vector" in str(vec):
    pass

# Either do this, which will test for 'vec' being exactly of type c4d.Vector
# or c4d.Vector4d:
if type(vec) in (c4d.Vector, c4d.Vector4d):
    pass
# Or do this, which will test if 'vec' is also of type c4d.Vector or 
# c4d.Vector4d, i.e. is respecting polymorphism. Which does not make much 
# sense here, since both Vector and Vector4d are atomic types. 
# This however is the recommended approach to type tesing in Python, because 
# usually you want and need to respect polymorphism.
if isinstance(vector, (c4d.Vector, c4d.Vector4d)):
    pass
            
                                    
# Also your string handling is more complicated than it needs to be (you should
# also stick to PEP8, specifically the line length here):
val = ("Vector(" + str(vec[0]*255) + ", " + str(vec[1]*255) + ", " + str(vec[2]*255) + ")")

# Use Pythons string formating instead, the values will be put in consecutive
# order into the curly brackets. There is a whole string formating mini
# language, which will allow you to do all sorts of stuff, like aligning text,
# converting between number formats and more. Check the Python docs on the
# subject if you want to know more.
print "Vector(r:{}, g:{}, b:{})".format(int(vec.x * 255), 
                                        int(vec.y * 255), 
                                        int(vec.z * 255))

Cheers,
zipit

@zipit Thanks! All great points. I was trying to check for instance of object initially, but was failing to find the correct syntax in this case. I got impatient and started hacking together solutions that still function even if not optimized/ideal.

I am so use to Adobe ExtendScript which is JavaScript based and Houdini VEX which is more python/JavaScript like, and their hscript which is Python based. So C4D python syntax can be just close enough to drive me nuts when I don’t find the correct answer. I’ve struggled with C4D python for a long time too. The docs really get confusing fast (for me at least)

One thing that helped me with Adobe ExtendScript is the object model graph they have in the docs. It showed the object flow hierarchy and each class name. So it was super easy to find every method and attribute associated with each. Almost linear in nature. I think also what help most was the object naming though, it matched more with the front end naming, so it was easy to connect the dots. That’s mostly where I struggle in the C4D docs, and confusion sets in fast for me. Like BaseContainer, Atom, Description, etc... I see the App > Object Panel > Object > Parameter > Value (as a very basic example)

Granted I never took a traditional route for learning coding, and am self taught. 🙂

Thanks again for the tips you keep mentioning. I really appreciate it.

Hi sorry to come late to the party, so to answers your initial questions:

  • DESC_CHANGED is only defined for intcustomgui (also used for float value) when the value is changed, so it's not as helpful as one may think.
  • DESC_DEFAULT, as said by zipit it's to the object, to properly set the default value, otherwise, you will get the default DataType value which may not be the default value of an object.

So I took another way to extract what changed and what not changed, by simply creating a new object and check the changed value. This also supports tag additions.

import c4d

class Parameter(object):
    # Represent a parameter
    def __init__(self, paramIdent, paramName, paramValue):
        self.paramIdent = paramIdent
        self.paramName = paramName
        self.paramValue = paramValue

    def __str__(self):
        return '"{1}", c4d.{0} {2}'.format(self.paramIdent, self.paramName, self.paramValue)
    
    def __repr__(self):
        return str(self)
        

def GetChangedParameter(bl2D):
    # Retrieve the changed parameter, by creating the BaseList2D and comparing the description and value
    
    # Create an object with default value
    cls = bl2D.__class__
    blTypeId = bl2D.GetType()
    
    newBl2D = cls(blTypeId)
    newBl2D.Message(c4d.MSG_MENUPREPARE, None)

    changedParams = []  # Will contains all the changed Parameter
    unwantedIds = [c4d.ID_BASELIST_ICON_COLOR, 
      c4d.ID_MG_MOTIONGENERATOR_EFFECTORLIST]  # List of excluded parameter because they are always different
    
    # Iterate teh description of the existing obj
    description = bl2D.GetDescription(c4d.DESCFLAGS_DESC_0)
    for bc, paramId, groupId in description:
        # if we dont want to deal with this parameter continue the loop
        if paramId[0].id in unwantedIds:
            continue
        
        # Ignore group
        if paramId[0].dtype == c4d.DTYPE_GROUP:
            continue
        
        # If a parameter is not within the newly created, something went wrong
        if not description.CheckDescID(paramId, [newBl2D]):
            raise ValueError("{0} not found in the created instance".format(paramId))
        
        # Try excecute, because some Datatype are not present in Python
        # here we retrieve the value of the parameter in the scene Bl2D and the newly created
        try:
            bl2DValue = bl2D[paramId]
            newBl2DValue = newBl2D[paramId]
            
            # If they are not equal, append a new parameter in the changedParams list
            if bl2DValue != newBl2DValue:
                newParam = Parameter(bc[c4d.DESC_IDENT], bc[c4d.DESC_NAME], bl2DValue)
                changedParams.append(newParam)
        except:
            pass
        
    return changedParams
        

def HierarchyIterator(bl2D):
    """
    A Generator to iterate over the Hierarchy
    :param bl2D: The starting object of the generator (will be the first result)
    :return: All objects under and next of the `bl2D`, so any BaseList2D
    """
    while bl2D:
        yield bl2D
        for opChild in HierarchyIterator(bl2D.GetDown()):
            yield opChild
        bl2D = bl2D.GetNext()
        
def GetAddedTags(obj, excludedTags):
    # Retrieve added tags by creating the object and look which tags are added or not
    if not isinstance(obj, c4d.BaseObject):
        return
    
    # Create a new obj
    objTypeId = obj.GetType()
    newObj = c4d.BaseObject(objTypeId)
    
    # Function which return a dict with key as Tag Type and entry are a list of tags, {tagType: [c4d.BaseTag]}
    def _GetTags(obj, excludedTags):
        tags = {}
        for tag in obj.GetTags():
            tagType = tag.GetType()
            if tagType in excludedTags:
                continue
            
            if tagType in tags:
                tags[tagType].append(tag)
                
            else:
                tags[tagType] = [tag]
                
        return tags
    
    # Retrieve Tags information
    tags = _GetTags(obj, excludedTags)
    newTags = _GetTags(newObj, excludedTags)
    
    missingTags = []  # will be filled with missing tags
    
    for tagId in tags:
        # A tag type is not present in the new one add it
        if tagId not in newTags:
            for t in tags[tagId]:
                missingTags.append(t)
                
            continue
                
        # obj present in the scene have more tag than the defualt one
        if len(tags[tagId]) > len(newTags[tagId]):
            missingTags.extend(newTags[len(tags[tagId]):])
            
                
    return missingTags
        
    


# Main function
def main():
    ignoredObjs = []
    ignoredTags = [c4d.Tphong]
    for obj in HierarchyIterator(doc.GetFirstObject()):
        if obj.GetType() in ignoredObjs:
            continue
        
        changedParams = GetChangedParameter(obj)
        addedTags = GetAddedTags(obj, ignoredTags)
        
        # Print obj Name
        if changedParams or addedTags:
            print(obj.GetName())
            
        # Print obj changed parameter
        for param in changedParams:
            print("{0}{1}".format(" "*2, param))
            
        # Print missing Tag
        for tag in addedTags:
            print("{0}Missing Tag: {1}".format(" "*2, tag.GetName()))
            
            # Print modified value for phong
            for param in GetChangedParameter(tag):
                print("{0}{1}".format(" "*4, param))

# Execute main()
if __name__=='__main__':
    main()

Regarding the Python documentation, we are of course looking to improve it, so if you have any advice, please feel free to give us. Just a side note each class you can see the parent class and children classes, so you can quickly find all the methods of a class. Here an example for the BaseList2D class f976e1a7-7990-478b-a11e-041ce6339f0d-image.png

Cheers,
Maxime.

@m_adam Wow, thanks Maxime for the explanation and code. I was not expecting that amount of effort.

I ran the code and encountered two errors so far. I believe one may be App version related possibly, and the other I am unsure.

So first the section in your GetChangedParameter function

 # List of excluded parameter because they are always different
unwantedIds = [c4d.ID_BASELIST_ICON_COLOR,
                         c4d.ID_MG_MOTIONGENERATOR_EFFECTORLIST]

I get this attribute error

AttributeError: 'module' object has no attribute 'ID_BASELIST_ICON_COLOR'

I am assuming this may be an ID added after R20. I am still using R20 for context. Once I remove it from the list the rest of the code will execute.

The second error I get is when encountering any polygon object. For example you can throw down any primitive shape and make it editable to test this.

When a polygon object is encounter this type error is thrown:

TypeError: Required argument 'vcnt' (pos 2) not found

My guess is that since it's a polygon object (which could be a native primitive made editable or a custom geometry imported by user) C4D has no direct reference to recreate the object in a default state?

So far those are the only two issues I have come across.

Hi @davidtorno sorry I overlooked the version in the post tag.
You are right ID_BASELIST_ICON_COLOR was added in R21. So you could remove it.

Regarding the second issue, you are also right, a PolygonObject/SplineObject have no history at all, so you can't trace them, even modeling operation done on them can't be retrieved at least by the way I propose.
You could do a SceneHook(only available in C++) to monitor the change made by a tool by listening to EVMSG_CHANGE (triggered when a EventAdd is processed) figured out if a polygon object changed (by iterating over each scene object, and checking their dirty bits), then retrieve the current tool and parameters, but as you can see it's a pretty complex task.

So in your case I would suggest to simply ignore edited object (so PolygonObject and SplineObject) by editing ignoredObjs variable like so

ignoredObjs = [c4d.Opolygon, c4d.Opoint, c4d.Ospline, c4d.Oline]

Cheers,
Maxime.

Hello @davidtorno,

without any further questions or replies, we will consider this topic to be solved by Monday and flag it accordingly.

Thank you for your understanding,
Ferdinand