Github Example group_nodes_r26 is broken.

Dunhou

Hi there !

I want wo get selected node or wires , but the github group_nodes_r26 has a problem happened, and I didn't find IsSelected . how do I fix this?

here is my material:

here is the console feedback:

Traceback (most recent call last):
  File "C:\Program Files\Maxon Cinema 4D 2023\resource\modules\python\libs\python310\maxon\data.py", line 84, in __getattribute__
    return Data_GetMember(self, name, o)
AttributeError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "scriptmanager", line 68, in <module>
  File "scriptmanager", line 51, in main
  File "C:\Program Files\Maxon Cinema 4D 2023\resource\modules\python\libs\python310\maxon\data.py", line 86, in __getattribute__
    return object.__getattribute__(self, name)
AttributeError: 'GraphNode' object has no attribute 'IsSelected'

ferdinand

Hello @Dunhou,

Thank you for reaching out to us and for pointing out the error in this script.

The script has not been updated yet for 2023 and is still using old Nodes API calls. The S26 method maxon.GraphNode.IsSelected was already deprecated in S26 in favor of the S26 method maxon.GraphModelHelper.IsNodeSelected. In 2023, the GraphNode method has been removed and you now must use maxon.GraphModelHelper.IsNodeSelected (2023.2).

I.e., you must change this:

# Create a list of the selected ones.
selectedNodes = []

for node in nodes:
    if node.IsSelected():
        selectedNodes.append(node)

to this:

# Create a list of the selected ones.
selectedNodes = []

for node in nodes:
    if maxon.GraphModelHelper.IsNodeSelected(node):
        selectedNodes.append(node)

As an FYI: A lot of functionalities have been moved from GraphNode and GraphModelRef to GraphModelHelper. We will update the GitHub script/provide a new one for 2023. Find below the full script updated for 2023.

Cheers,
Ferdinand

Code:

"""
Copyright: MAXON Computer GmbH
Author: Manuel Magalhaes
Description:
    Retrieve the selected node material and group the node that are selected.
    
Class/method highlighted:
    - MoveToGroup
    - IsSelected
"""
import c4d
import maxon


def main():
    # Retrieve the selected BaseMaterial
    mat = doc.GetActiveMaterial()
    if mat is None:
        raise ValueError("There is no selected BaseMaterial")

    # Retrieve the reference of the material as a node material.
    nodeMaterial = mat.GetNodeMaterialReference()
    if nodeMaterial is None:
        raise ValueError("Cannot retrieve node material reference")

    # Retrieve the current node space Id
    nodespaceId = c4d.GetActiveNodeSpaceId()

    # Retrieve the Nimbus reference for a specific node space
    nimbusRef = mat.GetNimbusRef(nodespaceId)
    if nimbusRef is None:
        raise ValueError("Cannot retrieve the nimbus ref for that node space")

    # Retrieve the graph corresponding to that node space.
    graph = nimbusRef.GetGraph()
    if graph is None:
        raise ValueError("Cannot retrieve the graph of this nimbus ref")

    # Get the root of the GraphNode
    root = graph.GetRoot()

    # Retrieve all nodes, child of the root node
    nodes = []
    root.GetChildren(nodes, maxon.NODE_KIND.NODE)

    # Create a list of the selected ones.
    selectedNodes = []

    for node in nodes:
        if maxon.GraphModelHelper.IsNodeSelected(node):
            selectedNodes.append(node)

    # Group all the selected nodes in an empty node.
    groupRoot = maxon.GraphNode()

    # To modify a graph, modification must be done inside a transaction. After
    # modifications are done, the transaction must be committed.
    with graph.BeginTransaction() as transaction:
        graph.MoveToGroup(groupRoot, maxon.Id("idOfMyGroup"), selectedNodes)
        transaction.Commit()

    # Pushes an update event to Cinema 4D
    c4d.EventAdd()


if __name__ == "__main__":
    main()

Dunhou

@ferdinand Hei thanks for point that, it worked as expected .

I noticed maxon api changed every version and almost the major part of sdk change log , and maxon api is not like c4d old api ( is more friendly to a beginner ) I know it's been repeated over and over，but more github examples please,

ferdinand

Hello @Dunhou,

I noticed maxon api changed every version and almost the major part of sdk change log

We are aware that this fact is disliked by especially technical artists. But the Nodes API is still under active development and probably will be for the intermediate foreseeable future. Some changes from time to time are therefore inevitable. But we usually do not just remove something, but first mark it as deprecated and then remove it one or two cycles later, giving third parties more time to adapt. For S26, GraphModelInterface::IsSelected in graph.h changed for example into this:

[[deprecated("Use GraphModelHelper static functions")]] MAXON_METHOD Result<Bool> IsSelected(const GraphNode& node);

The problem is that this information is not visible at all for Python developers and still could also be improved for C++. We are aware of the problem, and working on the quality of change notes is something we already did over the last cycles and are still doing. Mapping such information to Python is certainly something I would like to do, but my main focus was for now gathering C++ API change notes in a more consistent manner. For now, I would recommend having an eye on the C++ change notes as a Python developer. The color coded deprecated markup should make it fairly easy to find upcoming removals, see for example the 2023.2 C++ API change notes.

We are still working on improving API change notes for C++ and Python, because we are aware that it is crucial to clearly communicate our intentions with an API. I for example would like to make such information more searchable or pull it into the relevant documentary units. I.e., pull change notes also into the class, method, etc. descriptions, which are the subject of change. But that will be very hard to do with our current solutions might therefore have to wait a bit.

Cheers,
Ferdinand