Optimizing material count on a car glb model

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Hi All,

We bought a detailed Tesla S 2020 car model from Turbosquid recently to show in our car configurator. The object has about 20 odd animations, 332 odd Meshes and 75 materials.

The initial downloaded gltf/glb file that we received from Turbosquid was about 600MB along with the raw PNG textures that were being used. I compressed a lot of these textures (to jpeg) and got down the size of the model to 22MB at the moment. It renders fine, but it is still pretty heavy on the graphics card. (About 20-30FPS)

Looking at the model on Blender, I realized that the hierarchy is way too detailed and the materials are far too many. At the moment I see that there are about 332 draw calls happening on the GPU, (Triangle count is approximately 850,000). Now I know there is no direct answer for this but is re-topologising (Making a new hierarchy) the only way to fix this issue?. Also, Is manual merging of materials on Blender the only way to get the material counts down in our case?

The model uses a lot of PBR textures as well. Could the concept of baking be used in this case somehow?

I know my question could be classified as broad here, but any direction towards what I could do would really help here and would be appreciated. I don’t need ready-made solutions but just a direction which I can take here :slight_smile:

Cheers!
Srinivas

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You can try decimate modifier in Blender to reduce these 850k triangles. It has extremely random results - but is much faster than remesh / retopology.

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Aha. Let me try using the decimate modifier and see how much of a triangle count I can reduce before my model looks sharp :sweat_smile: is there anything I could do about the materials itself.?

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https://github.com/zeux/meshoptimizer or https://rapidcompact.com/ might be worth a look, as well.

2 Likes
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I don’t think 35 materials is too many tbh. But if you want, you could try removing the less significant ones in Blender File > Current File > Materials:

Screenshot 2020-10-11 at 09.14.03

Just delete one by one and see if anything meaningful is lost from the model (deleting a material in Blender File menu removes it from every place it was used at.)

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Thanks Don.Will check them out :slight_smile:

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Its 75 materials :sob: Is 75 within the limit :slight_smile: ? Yeah, I am trying to remove some of the less used materials at the moment.