SOLVED Get/Fetch Node from an Existing Xpresso Tag

Hi,

Is there a way to get/fetch a node from an existing xpresso tag? For instance, of all 5 existing math nodes, select a node with a particular name or a particular operation type (i.e. multiply as opposed to add).

In the documentation there is GetNode method but it is specific to port. Basically, what I am after is something like.

obj = doc.SearchObject("obj")
tag = obj.GetTag(c4d.Texpresso)
nodemaster = tag.GetNodeMaster()

# get/fetch a particular node  in  the list of nodes of nodemaster

Is this possible? Thank you for looking at my problem.

Hi @bentraje GvNode are standard BaseList2 that means you can iterate them as you can iterate object in the ObjectManager.

With that's said here is an example:

"""
Copyright: MAXON Computer GmbH

Author: Maxime Adam

Description:
    - Loops through all nodes from the Xpresso Tag of the selected object.
    - Checks if it's a Math Node.

Class/method highlighted:
    - c4d.modules.graphview.GvNodeMaster
    - c4d.modules.graphview.GvNode
    - GvNodeMaster.GetRoot()
    - GvNode.GetNext() / GvNode.GetUp() / GvNode.GetDown()
    - GvNode.GetOperatorID()

Compatible:
    - Win / Mac
    - R13, R14, R15, R16, R17, R18, R19, R20
"""
import c4d


def iterateNodes(node):
    """
    This function iterates over a BaseList2D, GvNode inherit from BaseList2D.
    :param node: GvNode to iterate.
    """
    while node:
        nodeName = node.GetName()
        isMathNode = node.GetOperatorID() == c4d.ID_OPERATOR_MATH
        
        # If it's a math node and set to multiply, prints the node name
        if isMathNode:
            isMultiply = node[c4d.GV_MATH_FUNCTION_ID] == c4d.GV_MUL_NODE_FUNCTION
            if isMultiply:
                print "Name: {0}".format(node.GetName())

        # If it's a group retrieves all inner GvNode.
        if node.IsGroupNode():
            iterateNodes(node.GetDown())

        node = node.GetNext()

def main():
    # Checks if selected object is valid
    if op is None:
        raise ValueError("op is none, please select one object.")

    # Retrieves the xpresso Tag
    xpressoTag = op.GetTag(c4d.Texpresso)
    if xpressoTag is None:
        raise ValueError("Make sure the selected object get an Xpresso Tag.")

    # Retrieves the node master
    gvNodeMaster = xpressoTag.GetNodeMaster()
    if gvNodeMaster is None:
        raise RuntimeError("Failed to retrieves the Node Master.")

    # Retrieves the Root node (the Main XGroup) that holds all others nodes
    gvRoot = gvNodeMaster.GetRoot()
    if gvRoot is None:
        raise RuntimeError("Failed to retrieves the Root Node.")

    # Iterates overs all nodes of this root node.
    iterateNodes(gvRoot)


if __name__=='__main__':
    main()

Cheers,
Maxime.

Thanks @m_adam. Works as expected.
My bad, I was looking at the documentation hierarchy erroneously (i.e c4d > modules > graphview > GvNode)

Just a note: I think the if Multiply: line is supposed to be if isMultiply:.

Thanks again. Have a great day ahead!