Collada scene from SketchUp can not be imported properly

[Frontrider]

Godot version

3.3.2.stable

System information

windows10/manjaro, GLS3

Issue description

When importing dae from Sketchup, the import gets several different errors. Importing the same dae file into blender then exporting it as dae always fixes it, but is not a working solution. Sketchup does not have GLTF support so this is the only format that can work.

Link to sketchup:
https://www.sketchup.com

Steps to reproduce

This dae file produces this error:
https://cdn.discordapp.com/attachments/275788728168087556/871370866452226058/terrain.dae
https://cdn.discordapp.com/attachments/275788728168087556/871370304478392330/2021-08-01_14-34-20.png

editor/collada/collada.cpp:1060 - Primitive type "polygons" is not well supported (concave shapes may fail). To ensure that the geometry is properly imported, please re-export using "triangles" or "polylist".

This was fixable by changing that "polylist" setting to "triangles".

With tringles enabled, we get this:
https://cdn.discordapp.com/attachments/275788728168087556/871376248692154408/terrain.dae

with this error:

 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.
 editor/collada/collada.cpp:1691 - Multiple instance_* not supported.

Minimal reproduction project

Drop the linked dae files into a blank godot project and import.

[akien-mga]

For the reference, there seems to be a glTF export addon for SketchUp, that might be worth trying: https://extensions.sketchup.com/extension/052071e5-6c19-4f02-a7e8-fcfcc28a2fd8/gltf-exporter

But fixing the DAE support is still worth looking into of course.

[Frontrider]

We checked that addon, and that is not an option.

[KenneyNL]

Since this is the only option to natively export models from SketchUp (the plug-in isn't great) I'd love to see this fixed, just ran into this issue myself. OBJ is too limiting.

[akien-mga]

Does COLLADA2GLTF help convert those scenes to something Godot supports best?

[KenneyNL]

I'd really not like to change my pipeline when importing models honestly. Unity supported SKP (SketchUp's native file format) so having to use a different file format is already a hassle, converting that (even when automated) just adds yet another step.

[akien-mga]

Well the point is that if it works, this can be automated in a way where you wouldn't even know that a conversion takes place.

Like Unity does when it "imports" .blend files by actually calling Blender on the command line to export to fbx.

Would also be worth testing https://extensions.sketchup.com/extension/052071e5-6c19-4f02-a7e8-fcfcc28a2fd8/gltf-exporter or any other glTF export plugin available. I know you don't want to change your workflow but it would still be useful to know what works and what doesn't. glTF 2.0 is the most comprehensive and best supported format in Godot, so anything that can go through this well tested import pipeline will be much more feature complete.

[KenneyNL]

@akien-mga Ah sorry, I misunderstood before and thought you meant I had to use that converter - not that it'd be integrated. I'm all for that, obviously!

I will be testing the glTF exporter plug-in and report back.

[akien-mga]

BTW if you have example DAE exports that you can share for testing, it could be useful to validate that #63072 actually solves your problems.

I tested with @Frontrider's https://cdn.discordapp.com/attachments/275788728168087556/871370866452226058/terrain.dae and it does solve the errors. The actual imported scene looks kind of the same to me, I'm not sure if the bug was just the error spam and that the scene actually is broken.

[akien-mga]

BTW if you have example DAE exports that you can share for testing, it could be useful to validate that #63072 actually solves your problems.

My findings so far are that COLLADA2GLTF doesn't do such a good job, at least on a few random DAE files I found in bug reports here.

So it would still be interesting to explore other avenues to improve the SketchUp workflow, given that our COLLADA exporter is difficult to maintain and overall COLLADA I/O in 3D software is notoriously problematic:

• Test the glTF export plugins for SketchUp. I found 3:
  • https://extensions.sketchup.com/extension/6caab93c-aa62-4637-be26-5d09ed7af997/sketch-up-gl-tf-exporter
  • https://extensions.sketchup.com/extension/7c51731a-5517-40aa-bd6d-700109837837/sim-lab-gltf-exporter-for-sketch-up
  • https://extensions.sketchup.com/extension/052071e5-6c19-4f02-a7e8-fcfcc28a2fd8/gltf-exporter
• Test FBX export from SketchUp. In Godot 3.x the FBX importer is quite limited so it might not work (but could be tested). In 4.0, we use FBX2glTF to perform the conversion and it works quite well in what we could see so far.
  • FBX2glTF needs to be downloaded from https://github.com/V-Sekai/FBX2glTF/releases and the path to this binary should be set in the Editor Settings at filesystem/import/fbx/fbx2gltf_path.

[taustin73]

I'm the Engineering Director for the SketchUp team and I will bring this up as an issue on the Collada exporter. We are actively working on a glTF exporter as well so stay tuned. (FYI: I came across this issue on Kenney's twitter feed.)

[aaronfranke]

@taustin73 What is the status of this? Does SketchUp have glTF support? I could not find a blog post about this from a Google search. The website seems to mention only exporting SKP, PNG, STL, not Collada or glTF.