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Help Understanding and Reconstructing Assembly Transformations Outside Onshape
Clayton_Krause
Member Posts: 2 PRO
Hello — I’m looking for guidance on how to work around Onshape’s assembly transformation behavior when processing assemblies externally.
Description:
I have a top-level assembly that contains multiple inserted sub-assemblies, each with varying nesting depth. In Onshape, every sub-assembly is positioned correctly in assembly space using mates.
My goal is to:
- Export each sub-assembly individually (via Parasolid X_T) in its own local part space for downstream mesh conversion.
- Separately export the full top-level assembly and programmatically replace its inserted sub-assemblies with those pre-exported local assets.
To do that, I need to know each sub-assembly’s offset and orientation within the top-level assembly. The challenge is that Onshape appears to push all transformation data down to the leaf parts, so intermediate sub-assemblies carry no transform — only their child parts have absolute (world-space) transforms.
I can trace consistent BTI/InstanceId paths between the API response and my exported data, and I’ve been trying to use the Assembly Definition API to reconstruct sub-assembly transforms from that. However, I haven’t yet found a reliable method to derive those intermediate offsets or re-establish the hierarchy outside Onshape.
Has anyone solved this or found a practical way to recover sub-assembly transformation data from Onshape’s API exports?
Thanks in advance for any insight.
Answers
Posted to "general" category by mistake. Request made to admin for it to be moved to "community support".