Missing CAD Patch UVs on STEP Import

InstaLOD
1

Hi there,

I previously used InstaLOD Studio to process .stp files where UVs were automatically generated on import. These UVs were based on CAD surface patches (mostly rectangular islands per surface), similar to what 3ds Max produces. While simple, these patch-based UVs were very useful for further processing.

After reinstalling InstaLOD on a new workstation (2024 v6.2), this behavior seems to have changed. A few observations:

  • Importing STEP files now results in no UV layers at all
  • The same STEP files previously produced UVs without additional steps
  • 3ds Max still generates patch-based UVs from the same files automatically
  • No obvious settings related to UV preservation found in the UI, only unwrap features which discard the original patch-based structure

It’s possible I may have missed a step or setting I originally used, as my previous workflow was based on a preset and required only minimal interaction.

Was there a change in how CAD surface parameterization → UV conversion is handled on import? Or is there a specific setting, module, or step required to restore this behavior?

Thanks!

2

Hello @AndyK and welcome to our community!

Please update your InstaLOD version to the 2026 release. It’s the most recent version you can find on https://cloud2.instalod.io/. The issue should be fixed in this build. In case it still doesn’t work, please let me know.

Thanks!

3

Thanks! :slight_smile:

I am now running InstaLOD Studio 2026 v7.0 (build Feb 6 2026), but I’m still encountering the same issue.

Up to now, my workflow has been very minimal and based on these steps:

  • Open Scene (.stp)
  • Leave Import dialog at defaults
  • Apply a CAD LiveLink preset (adjusting MaxDeviation, MaxEdgeLength, MaxAngle, UpAxis)
  • Retessellate
  • Export to .fbx (UV export enabled)

This used to be sufficient and resulted in patch-based UVs being present.

Some additional information:

  • InstaLOD Studio UV Viewer stays empty
  • Blender reports an empty list when querying UV layers via Python
  • I also tested other export formats to rule out FBX-specific issues, with the same result

I am attaching my current profile .json in case that is of any use.

Thanks for your time!
profile_sample.zip (1.5 KB)

4

Hey @AndyK,

I followed up on it again and unfortunately the fix didn’t make it into the current build. It will be available in a follow up build soon. Sorry that I do not have better news to share.

Thanks!

5

Hi @debe,

Thanks for the update - that’s great to hear nonetheless! Good to know this behavior is being addressed. I’m looking forward to its availability again in an upcoming build.

Appreciate you checking into this!

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