How to scale all objects in a scene at once?

j_vogel

I need to reactivate this thread. Everything that is posted here and in other posts doesn't really solve my problem.
I just want to have the same functionality as the scale project button but automated.
We have fbx imports that are too small (we can not change the scale in the export settings as there are no settings).
With all the stuff from this thread here the only thing that happens is, that we can change the project scale but not the actual scale of the 3D data which the Scale project button does.

I mean if I want to have everything 10 times bigger I can change the project scale to 10 centimeters. So when copying it to a new scene or loading it as XRef with a project scale of 1 centimeter it seems to work but we already had problems with this workflow in the past with some shader scales or something that did not work properly.

So we changed to just use the "Scale project" button and type 10 in the target scale and this does the job.
I wanted to recreate this exact behaviour but the only way I see at the moment to just recreate this whole function by myself as there seems no way to scale your project. You can change the project scale or use a callcommand for the button but that just opens the window and I have to manually type in 10 and hit enter.

What can I do to solve this problem? It seems so simple but I can not find a solution for that.

ferdinand

Hello @j_vogel,

Welcome to the Maxon developers forum and its community, it is great to have you with us!

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The parameter DOCUMENT_DOCUNIT in a document is just something that is added to things like the coordinate manager, to set the unit and a multiplier for the numbers shown there. It will not scale the actual geometries (as it otherwise would be destructive) and therefore does not affect the view port.

To scale all elements in the scene, you must scale all elements . You can use the command which we implemented for that, what is talked about above and which can be invoked with the button in the document scale settings. But you then have to use its UI, which is I guess not what you want. So, you would have write something like that yourself. But there is currently no premade scene traversal in Python which can be a bit daunting for beginners (will change with the next major release). Carrying out the scaling itself is not that hard, although this complexity can also vary based on the content. Since I know you have beta access: You can also pick the latest beta build, the traversal stuff is already in there.

Cheers,
Ferdinand

Code

"""Demonstrates how to scale all objects in a scene by a given factor.
"""

import c4d

SCALE_FACTOR: c4d.Vector = c4d.Vector(2) # Scale factor for the objects, we pick a uniform scale of 2.
doc: c4d.documents.BaseDocument          # The currently active document.

def IterateTree(node: c4d.GeListNode, yieldSiblings: bool = False) -> c4d.GeListNode:
    """Iterates over all descendants of the given #node and optionally its next siblings.

    In the next major release, there will be (finally) built-in scene traversal functions in Python. The one
    to pick for this case would be `mxutils.IterateTree`. Its signature is compatible with what I did here.
    """
    def iterate(node: c4d.GeListNode) -> c4d.GeListNode:
        if not node:
            return
        
        yield node
        for child in node.GetChildren():
            yield from iterate(child)

    while node:
        yield from iterate(node)
        node = node.GetNext() if yieldSiblings else None

def main() -> None:
    """Called by Cinema 4D when the script is being executed.
    """
    # Iterate over all objects in the document and scale them.
    for node in IterateTree(doc.GetFirstObject(), yieldSiblings=True):
        node.SetMl(node.GetMl() * c4d.utils.MatrixScale(SCALE_FACTOR))
        
    c4d.EventAdd()


if __name__ == '__main__':
    main()

edit: you should of course use the local and not global matrix, as you otherwise will scale things multiple times.