How to completely free mesh vertex data from CPU memory after GPU upload?

[Anehta]

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Context:
I'm working on a project where CPU memory usage is a critical concern. After uploading mesh data to the GPU, I need to completely free all vertex-related information from CPU memory.

Problem:
My application's memory usage jumps from ~300MB to ~800MB after loading meshes, and this 500MB of vertex data remains in CPU memory even after rendering begins. I've tried using render_world but it doesn't seem to help - the memory usage stays at 800MB.

What I've tried:

• Using render_world to access render-specific resources
• The mesh data still seems to be retained in the main world

Question:

1. Is Bevy intentionally keeping a CPU-side copy of all vertex data even after GPU upload?
2. Is there a way to completely drop/free the vertex buffers from CPU memory after they've been uploaded to the GPU?

My use case:

• I don't need CPU-side mesh features like MeshPicking, physics mesh queries, or any CPU-based mesh operations
• My application is purely for rendering
• CPU memory footprint is critical for my application
• Once the mesh is on the GPU, I have no need to access the vertex data from the CPU side

Expected behavior:
After GPU upload is complete, I'd like to free the ~500MB of vertex data from CPU memory, bringing the memory usage back closer to the base 300MB.

Is this currently possible in Bevy, or would this require a feature request/custom implementation? If it requires custom implementation, could you point me to the relevant systems/resources I should look into?

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[JMS55]

Use https://docs.rs/bevy/latest/bevy/render/render_asset/struct.RenderAssetUsages.html#associatedconstant.RENDER_WORLD.