There is a known issue with using ZSketch on an armature. There are no problems with creating the armature, but once starting to ZSketch onto it a crash can occur that gives a message of "INTERNAL ERROR.\List.cpp Line:1206"
We are currently investigating the issue and will update this article when more information becomes available. If a workaround is not possible, the issue should be fixed in an upcoming update.
Matthew Yetter
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