Is this is the right place to report a bug on SketchUp Datasmith Exporter?
I’ve been using the Sketchup Datasmith Exporter for SketchUp 2018 with Unreal Engine 4 and 5 previously without problems. When trying the latest SketchUp Datasmith Exporter with SketchUp 2023 the normals for some objects gets screwed up, making the lighting look bad. I have verified with the “Probes” plugin that the normals are OK in SketchUp and then I have also verified the normals are screwed up in UE. The same model exports fine in SketchUp 2018 with Datasmith Exporter 4.24.1 and imports fine in UE 5.3.1, so it must be a regression in later versions of the exporter plugin.
It is probably the same bug as reported here:
The proposed workaround of exploding and regrouping seems to work, but my model is huge so this will be time consuming and it can be very hard to notice for smaller objects.
Any hopes of getting this fixed in future releases?
I’m sad to hear you’ll not fix it earlier. Don’t you have any means of doing point releases/fix regressions on existing releases if they are broken? I don’t know when 5.5 will even be out but working in SketchUp 2018 for months severely affects my workflow as I cannot easily import models from 3d warehouse for example.
Or consider open sourcing the exporter so the community can fix it for ya
Thanks for the hint. I didn’t know the plugin source was available within the unreal engine source.
I managed to build it and had a look at it. I think the bug is in line 380 of DatasmithSketchUpMesh.cpp where the TransformNoTranslation variable is used instead of the TransformInverse created earlier. The TransformInverse is otherwise just an unused variable (which would’ve been caught by static code analysis).
Changing this seems to have fixed it for me! Verified in SketchUp 2023 & 2024 with UE 5.3.2 and a rather complex model but also in a minimal reproduction model and inspecting the normals in UE.
