Some 3D objects looks deformed/destroyed in the imported model

[waseemkhan1989]

Hi!

Now, I can successfully import glb files on Quest but some objects in my model looks deformed or destroyed. Here is an example of a car. The image is the original one

This is the one imported through GLTFast on Quest:

How can this issue be corrected?

[atteneder]

Thanks for reporting.

Very strange :/

The original image is not from Unity/glTFast, right? From what is it then?

Can you provide the model?

You can also cross-check with alternative glTF viewers like this great one.

[waseemkhan1989]

@atteneder Sorry for late replying. I was busy in moving to a new city. For the first picture, I used

3D viewer and second picture is tested with GLTFast on Quest. Thanks for sharing the link of GLTF viewer.

Please find attached the model.

DWG1_Halle.zip

There are also other models with which I am facing the same problem with GLTFast.
Point to be noted! with Unity GLTF library, I am not facing this problem.

Any solution?

[atteneder]

What I observed so far:

I'm using Unity's Matrix4x4.rotation and Matrix4x4.lossyScale to decompose the Matrix. This algorithm seem to break on objects with:

• negative uniform scale
• 90° rotation in X
• 45° rotation in Y

One workaround is to not use negative scale.

I'll have to investigate if other implementations are more robust.

[atteneder]

fix is in the making!

@waseemkhan1989 Would you mind it if I share screenshots of your model for educational purpos in my blog?

[waseemkhan1989]

@atteneder Yeah sure:). I have no problem with it:)