Still not possible to find out what's visible in the Timeline?

[Cairyn]

Thank you, @PluginStudent . I have tried to translate the C++ code from the example into a basic Python script that just writes the GetBranchInfo tree to the console; sadly there is a mysterious crash/hang somewhere...

import c4d
from c4d import gui


emCount = 0

def showBranchInfo(depth, obj):
    global emCount

    # Validity check
    if obj == None: return

    # Object output
    emCount += 1
    print "  " * depth, "Count=", emCount, "(object)"
    if isinstance(obj, c4d.documents.BaseDocument):
        print "  " * depth, "DOC:", obj.GetDocumentName()
    elif not isinstance(obj, c4d.BaseList2D):
        print "  " * depth, "Not a BaseList2D: ", obj
        return
    else:
        print "  " * depth, "OBJ:", obj.GetName()

    bis = obj.GetBranchInfo()
    if bis == None or len(bis) == 0:
        return
    for bi in bis: # list of dict{‘head’, ‘name’, ‘id’, ‘flags’}
        if len(bi) == 0: return # ### Test
        listHead = bi['head']
        nodeName = bi['name']

        # List head output
        emCount += 1
        node = None
        print "  " * (depth+1), "Count=", emCount, "(list head)", nodeName
        if listHead == None:
            print "  " * (depth+1), "No list head"
        elif not isinstance(listHead, c4d.GeListHead):
            print "  " * (depth+1), "Not a GeListHead:", listHead
        else:
            print "  " * (depth+1), nodeName, listHead
            node = listHead.GetFirst()

        # Content of sublist branch
        locCount = 0
        if node == None:
            print "  " * (depth+2), "Empty list"
        while node != None:
            emCount += 1
            print "  " * (depth+2), "El:", locCount, node
            locCount += 1
            if isinstance(node, c4d.BaseList2D):
                showBranchInfo(depth + 3, node)
                # no else case; node was already printed
            node = node.GetNext()
    # missing here: recurse into children of "node" or "obj"


def main():
    print " "
    print "GetBranchInfo"
    print "============="
    showBranchInfo(1, doc)

if __name__=='__main__':
    main()

If I limit emCount or depth to certain values, this recursion works fine (as mentioned in the code it's not going down into the child lists of a BaseObject but that's a thing I can add later).
If I just run the code with no limits, C4D hangs (and in one instance even crashed with an access violation) while doing... something. Even after two days of experimenting, I have not found the exact point where it fails. (Half of the code is already validation...) I guess I will need to set up a complete debugging environment to catch the culprit... before even returning to the original question...

[PluginStudent]

Not sure if it is related to your crash, but I have never seen someone using isinstance() this way.

In the C4D API, there is IsInstanceOf() to check for inheritance or type. See also Type.

[Cairyn]

@PluginStudent isinstance is the plain Python class comparison. IsInstanceOf() does not work here because it compares against type constants, and there is (AFAIK) no such constant for BaseDocument or BaseList2D or GeListHead.

EDIT: Oh, I'm stupid. I just saw that such a constant is used in the original example... okay, let's try that...

[Cairyn]

@PluginStudent No, didn't work with IsInstanceOf either.

For completeness: Tbasedocument and Tbaselist2d exist but are only documented in the C++ manual; missing in Python. Tgelisthead does not exist in either, so I still need to check the class against that with the Pythonic isinstance.

[m_adam]

Hi Just to let you know its seems there is currently a bug somewhere (still have to figure out) but to avoid any issue check if the returned GeListHead and then if you iterate over all its children that each c4dAtom returned is alive with C4DAtom.IsAlive before doing anything on it(e.g.s print them).

That should fix your issue.

Cheers,
Maxime.

[Cairyn]

@m_adam Thank you, unfortunately that didn't work either... I check the object, the list head, and the list nodes all for being alive, and I do not get any output that they aren't. The crashes continue.

I have compiled the SDK, and the "Active Object Properties" dialog works fine even in places where the Python script hangs. So, it might be a Python-only issue.

So far, I think that these places are when the script encounters a "Tags" object (type 200001048). The first place I saw this was under ProjektHooks/PLKHUD/PSUNDOHEAD/PKHOP. When I skipped that branch explicitly, the next place of crash was under Modeling Objects Hooks/Modeling Objects Branch/Plane Manipulator and Pivot Manipulator (both branches contain a "Tags" element). Didn't continue after that.

However, trying to exclude these node types didn't help either. Apparently, the objects are so volatile that any way of touching them creates the crash already.
(Since the scene tags also hide under these nodes, I do not want to exclude them, anyway.)

Here's the code I tried last:

import c4d
from c4d import gui

emCount = 0
handledList = []

def showBranchInfo(depth, obj, f):
    global emCount, handledList, maxCount, dialogCount

    try:
        # Validity check
        if obj == None: return
        if obj in handledList:
            print "Already handled! : ", obj
            print >>f, "Already handled! : ", obj
            f.flush()
            return
        else:
            handledList.append(obj)
        if not obj.IsAlive():
            print "Object not alive!"
            print >>f, "Object not alive!"
            f.flush()
            return
        if obj.GetType() == 200001048:
            print "Object is 200001048!"
            print >>f, "Object is 200001048!"
            f.flush()
            return
    except:
        print >>f, "ERROR in validity check"
        f.flush()
        return

    try:
        # Object output
        emCount += 1
        print "  " * depth, "Count=", emCount, "(object)"
        print >>f, "  " * depth, "Count=", emCount, "(object)"
        f.flush()
        if isinstance(obj, c4d.documents.BaseDocument):
            print "  " * depth, "DOC:", obj.GetDocumentName()
            print >>f, "  " * depth, "DOC:", obj.GetDocumentName()
            f.flush()
            # this is also a BaseList2D so we can continue
        elif not isinstance(obj, c4d.BaseList2D):
            print "  " * depth, "Not a BaseList2D: ", obj
            print >>f, "  " * depth, "Not a BaseList2D:", obj
            f.flush()
            return
        else:
            print "  " * depth, "OBJ:", obj.GetName()
            print >>f, "  " * depth, "OBJ:", obj.GetName()
            f.flush()
    except:
        print >>f, "ERROR in object output"
        f.flush()
        return

    try:
        child = obj.GetDown()
        if child != None:
            while child:
                showBranchInfo(depth + 1, child, f)
                child = child.GetNext()
    except:
        print >>f, "ERROR in subobject recursion"
        f.flush()
        return

    try:
        bis = obj.GetBranchInfo()
        if bis == None:
            print "ERROR: no branch info retrieved"
            print >>f, "ERROR: no branch info retrieved"
            f.flush()
            return
        # empty branch info is allowed, so no len() check!
    except:
        print >>f, "ERROR in GetBranchInfo"
        f.flush()
        return

    try:
        for bi in bis: # list of dict{‘head’, ‘name’, ‘id’, ‘flags’}

            try:
                if len(bi) == 0:
                    print "ERROR: no entries in dict list"
                    print >>f, "ERROR: no entries in dict list"
                    f.flush()
                    return
                listHead = bi['head']
                nodeName = bi['name']
                # print bi['id']
                # print bi['flags']
            except:
                print >>f, "ERROR in dict list check"
                f.flush()
                return

            try:
                # List head output
                emCount += 1
                node = None
                print "  " * (depth+1), "Count=", emCount, "(list head)", nodeName
                print >>f, "  " * (depth+1), "Count=", emCount, "(list head)", nodeName
                f.flush()
                # Crash irgendwo hier
                if listHead == None:
                    print "  " * (depth+1), "No list head"
                    print >>f, "  " * (depth+1), "No list head"
                    f.flush()
                elif not listHead.IsAlive():
                    print "List head not alive!"
                    print >>f, "List head not alive!"
                    f.flush()
                elif not isinstance(listHead, c4d.GeListHead):
                    print "  " * (depth+1), "Not a GeListHead:", listHead
                    print >>f, "  " * (depth+1), "Not a GeListHead:", listHead
                    f.flush()
                else:
                    print "  " * (depth+1), nodeName, listHead
                    print >>f, "  " * (depth+1), nodeName, listHead
                    f.flush()
                    node = listHead.GetFirst()
            except:
                print >>f, "ERROR in list head output"
                f.flush()
                return

            try:
                # Content of sublist branch
                locCount = 0
                if node == None:
                    print "  " * (depth+2), "Empty list"
                    print >>f, "  " * (depth+2), "Empty list"
                    f.flush()
                while node != None:
                    if node.IsAlive():
                        if node.GetType() != 200001048:
                            emCount += 1
                            print "  " * (depth+2), "El:", locCount, node
                            print >>f, "  " * (depth+2), "El:", locCount, node
                            f.flush()
                            locCount += 1
                            if isinstance(node, c4d.BaseList2D):
                                showBranchInfo(depth + 3, node, f)
                                # no else case; node was already printed
                        else:
                            print "List node is 200001048!"
                            print >>f, "List node is 200001048!"
                            f.flush()
                            return
                    else:
                        print "List node not alive!"
                        print >>f, "List node not alive!"
                        f.flush()
                    node = node.GetNext()
            except:
                print >>f, "ERROR in sublist branch handling"
                f.flush()
                return

        # missing here: recurse into children of "node" or "obj"
    except:
        print >>f, "ERROR in dictionary loop"
        f.flush()
        return

    try:
        print >>f, "  " * depth, "Returning from depth:", depth
        f.flush()
    except:
        print >>f, "ERROR in return"
        f.flush()
        return


def main():
    print " "
    print "GetBranchInfo"
    print "============="
    f = open("L:/getbranchinfo.txt", "at")
    showBranchInfo(1, doc, f)
    f.close()


if __name__=='__main__':
    main()

You can happily ignore the try/except blocks, as they never caught any error.
Considering that the code now consists of 80% error checking, this is a very frustrating exercise.

Interestingly, my initial example that uses GetCTracks() works fine (for what it does) and does not crash, even when handling (scene) tags. I suspect the issue ultimately lies in the GetBranchInfo() function somewhere.

[m_adam]

creating a cube and call op.GetBranchInfo is enough to trigger a crash, since its a C++ crash, there is no room for python to catch it.

[Cairyn]

@m_adam oops... didn't expect that, since the Active Object Properties sample works fine (solely in C++).

[Cairyn]

Okay, it's definitely the Tags node. I added some code to check for the name "Tags" in the list returned by GetBranchInfo() to skip that dictionary entry before even the list head is touched. That works, the recursion/iteration is running through without crash.

Of course, that makes the scene tags disappear from the list, so I also added in an else case that explicitly calls GetTags() on the original object, and continues the recursion with any returned tags.

For testing, I also added a collector list for the tracks (which were the original goal of this exercise...) and print the tracks at the end of the code. For a few test scenes, this apparently works; I have no idea about the overall soundness and completeness of this workaround though.

Here's the code for anyone who might face the same issue:

import c4d
from c4d import gui

emCount = 0
handledList = []
tracks = []

def showBranchInfo(depth, obj, f):
    global emCount, handledList, maxCount, dialogCount, tracks

    # Validity check
    if obj == None: return
    if not obj.IsAlive():
        print "Object not alive!"
        print >>f, "Object not alive!"
        f.flush()
        return
    if obj.GetType() == 200001048:
        print "Object is 200001048!"
        print >>f, "Object is 200001048!"
        f.flush()
        return
    if obj in handledList:
        print "Already handled! : ", obj
        print >>f, "Already handled! : ", obj
        f.flush()
        return
    else:
        handledList.append(obj)

    # Object output
    emCount += 1
    print "  " * depth, "Count=", emCount, "(object)"
    print >>f, "  " * depth, "Count=", emCount, "(object)"
    f.flush()
    if isinstance(obj, c4d.documents.BaseDocument):
        print "  " * depth, "DOC:", obj.GetDocumentName()
        print >>f, "  " * depth, "DOC:", obj.GetDocumentName()
        f.flush()
        # this is also a BaseList2D so we can continue
    elif not isinstance(obj, c4d.BaseList2D):
        print "  " * depth, "Not a BaseList2D: ", obj
        print >>f, "  " * depth, "Not a BaseList2D:", obj
        f.flush()
        return
    else:
        print "  " * depth, "OBJ:", obj.GetName()
        print >>f, "  " * depth, "OBJ:", obj.GetName()
        f.flush()

    # assemble the tracks of the object
    addTracks = obj.GetCTracks() # returns a list
    tracks.extend(addTracks)

    # go through the children of the object if present
    child = obj.GetDown()
    if child != None:
        while child:
            showBranchInfo(depth + 1, child, f)
            child = child.GetNext()

    # check the branch info and go into all dependent branches
    bis = obj.GetBranchInfo()
    if bis == None or len(bis) == 0:
        print "  " * (depth+1), "No branch info retrieved, or empty"
        print >>f, "  " * (depth+1), "No branch info retrieved, or empty"
        f.flush()
        return

    for bi in bis: # list of dict{‘head’, ‘name’, ‘id’, ‘flags’}

        if len(bi) == 0:
            print "ERROR: no entries in dict list"
            print >>f, "ERROR: no entries in dict list"
            f.flush()
            return
        nodeName = bi['name']
        if nodeName != "Tags":
            listHead = bi['head']
            # print bi['id']
            # print bi['flags']

            # List head output
            emCount += 1
            node = None
            print "  " * (depth+1), "Count=", emCount, "(list head)", nodeName
            print >>f, "  " * (depth+1), "Count=", emCount, "(list head)", nodeName
            f.flush()
            # Crash irgendwo hier
            if listHead == None:
                print "  " * (depth+1), "No list head"
                print >>f, "  " * (depth+1), "No list head"
                f.flush()
            elif not listHead.IsAlive():
                print "List head not alive!"
                print >>f, "List head not alive!"
                f.flush()
            elif not isinstance(listHead, c4d.GeListHead):
                print "  " * (depth+1), "Not a GeListHead:", listHead
                print >>f, "  " * (depth+1), "Not a GeListHead:", listHead
                f.flush()
            else:
                print "  " * (depth+1), nodeName, listHead
                print >>f, "  " * (depth+1), nodeName, listHead
                f.flush()
                node = listHead.GetFirst()

            # Content of sublist branch
            locCount = 0
            if node == None:
                print "  " * (depth+2), "Empty list"
                print >>f, "  " * (depth+2), "Empty list"
                f.flush()
            while node != None:
                if node.IsAlive():
                    if node.GetType() != 200001048:
                        emCount += 1
                        print "  " * (depth+2), "El:", locCount, node
                        print >>f, "  " * (depth+2), "El:", locCount, node
                        f.flush()
                        locCount += 1
                        if isinstance(node, c4d.BaseList2D):
                            showBranchInfo(depth + 3, node, f)
                            # no else case; node was already printed
                    else:
                        print "List node is 200001048!"
                        print >>f, "List node is 200001048!"
                        f.flush()
                        return
                else:
                    print "List node not alive!"
                    print >>f, "List node not alive!"
                    f.flush()
                node = node.GetNext()
        else:
            print "Tags skipped!"
            print >>f, "Tags skipped!"
            f.flush()
            if isinstance(obj,c4d.BaseObject):
                taglist = obj.GetTags()
                print "  " * (depth+2), "Tag list, length=", len(taglist)
                print >>f, "  " * (depth+2), "Tag list, length=", len(taglist)
                f.flush()
                for tag in taglist:
                    showBranchInfo(depth + 3, tag, f)

    # missing here: recurse into children of "node" or "obj"

    print >>f, "  " * depth, "Returning from depth:", depth
    f.flush()


def main():
    global tracks
    print " "
    print "GetBranchInfo"
    print "============="
    f = open("L:/getbranchinfo.txt", "at")
    showBranchInfo(1, doc, f)
    for track in tracks:
        print track
        print >>f, track
    f.close()


if __name__=='__main__':
    main()

---

(also, unsolicited advertising because I really spend too much time with this)
https://www.patreon.com/cairyn
there you go!

[m_adam]

Hi, I found the issue, unfortunately, nothing on your side you can do to fix it.

I marked this topic as solved, and will bump the topic once a fix is included in a public release.
Keep in mind this is a Python only issue.

Cheers,
Maxime.

[Cairyn]

@m_adam okay, good that it's found... I guess I can go with the code above for now that excludes tags explicitly and gathers them in a different recursion.

As per the original issue (there is no function in the API that returns the currently visible tracks in timeline n), I guess I would need to make a requirement/suggestion on Maxon's site? Or is something like this planned already?

[m_adam]

The bug is fixed in R23.

Cheers,
Maxime