GetMg() doesn't update on objects affected with Align to Spline Tag?

[bentraje]

Hi,

I have an object that is constrainted to a spline through align to spline tag.

The problem is when I run a GetMg().off on before and after I revise the tag, I get the same result instead of having different values.

What am I missing?

import c4d


def main():
    doc = c4d.documents.GetActiveDocument()

    joint = c4d.BaseObject(1019362)
    doc.InsertObject(joint)
    spline = c4d.BaseObject(5181)
    doc.InsertObject(spline)

    spline_tag = c4d.BaseTag(5699)
    joint.InsertTag(spline_tag)
    spline_tag[c4d.ALIGNTOSPLINETAG_LINK] = spline

    spline_tag[c4d.ALIGNTOSPLINETAG_POSITION] = 0
    c4d.EventAdd()
    print (joint.GetMg().off) # Vector(0, 0, 0)
    spline_tag[c4d.ALIGNTOSPLINETAG_POSITION] = 0.2
    c4d.EventAdd()
    print (joint.GetMg().off) # still Vector(0, 0, 0)

    c4d.EventAdd()
if __name__ == '__main__':
    main()

[i_mazlov]

Hi @bentraje,

you're doing everything right. The only step you're missing is to reevaluate the scene using ExecutePasses after changing the Align to Spline tag position. You can call it the following way:

doc.ExecutePasses(None, True, True, True, c4d.BUILDFLAGS_NONE)

Note, you should use c4d.BUILDFLAGS_0 instead, if you run c4d earlier than R20. This is how you can use it in a generic way:

buildFlag = c4d.BUILDFLAGS_NONE if c4d.GetC4DVersion() > 20000 else c4d.BUILDFLAGS_0
doc.ExecutePasses(None, True, True, True, buildFlag)

Cheers,
Ilia

[bentraje]

@i_mazlov

Gotcha. Thanks. Works as expected.