Add release notes for meshlet BVH culling #20526
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atlv24
reviewed
Aug 12, 2025
| The screenshot above has 130,000 dragons in the scene, each with about 870,000 triangles, leading to over *115 billion* total triangles in the scene. | ||
| However, this still runs at 60 fps on an RTX 4070 at 1440p, with most of the time being due to the instance upload CPU bottleneck mentioned above (taking 14 ms of CPU time). | ||
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| Speaking of GPU cost, the scene above renders in about 3.5 ms on the 4070, with ~3.1 ms being spent on the geometry render and ~0.4 ms on the material evaluation. |
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Suggested change
| Speaking of GPU cost, the scene above renders in about 3.5 ms on the 4070, with ~3.1 ms being spent on the geometry render and ~0.4 ms on the material evaluation. | |
| Speaking of GPU cost, the scene above renders in about 3.5 ms on a 4070, with ~3.1 ms being spent on the geometry render and ~0.4 ms on the material evaluation. |
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I was referring to the 4070 + 1440p combo mentioned above
atlv24
reviewed
Aug 12, 2025
Co-authored-by: atlv <[email protected]>
JMS55
reviewed
Aug 12, 2025
Co-authored-by: JMS55 <[email protected]>
JMS55
reviewed
Aug 12, 2025
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| (TODO: Embed example screenshot here) | ||
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| Bevy's virtual geometry has been greatly optimized with BVH-based culling, leading to almost true scene-complexity invariance on the GPU. |
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Suggested change
| Bevy's virtual geometry has been greatly optimized with BVH-based culling, leading to almost true scene-complexity invariance on the GPU. | |
| Bevy's virtual geometry has been greatly optimized with BVH-based culling, making the cost of rendering nearly independent of scene geometry. (Then write something here about 120k vs 1 million instances). |
JMS55
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Aug 12, 2025
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| Bevy's virtual geometry has been greatly optimized with BVH-based culling, leading to almost true scene-complexity invariance on the GPU. | ||
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| This gets rid of the previous cluster limit that limited the world to 2^24 clusters (about 4 billion triangles). |
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Suggested change
| This gets rid of the previous cluster limit that limited the world to 2^24 clusters (about 4 billion triangles). | |
| This also gets rid of the previous cluster limit that limited the world to 2^24 clusters (about 4 billion triangles). |
JMS55
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Aug 12, 2025
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| There are now *no* hardcoded limits to scene size, only unique instance limits due to VRAM usage (since streaming is not yet implemented), | ||
| and total instance limits due the current architecture requiring all instances to be uploaded to the GPU every frame. |
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Suggested change
| There are now *no* hardcoded limits to scene size, only unique instance limits due to VRAM usage (since streaming is not yet implemented), | |
| and total instance limits due the current architecture requiring all instances to be uploaded to the GPU every frame. | |
| There are now *no* hardcoded limits to scene size. In practice you will only be limited by asset VRAM usage (since streaming is not yet implemented), | |
| and total instance count due the current code requiring all instances to be re-uploaded to the GPU every frame. |
JMS55
reviewed
Aug 12, 2025
| and total instance limits due the current architecture requiring all instances to be uploaded to the GPU every frame. | ||
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| The screenshot above has 130,000 dragons in the scene, each with about 870,000 triangles, leading to over *115 billion* total triangles in the scene. | ||
| However, this still runs at 60 fps on an RTX 4070 at 1440p, with most of the time being due to the instance upload CPU bottleneck mentioned above (taking 14 ms of CPU time). |
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I don't think this sentence would mean much to people not very familiar with the rendering code.
JMS55
reviewed
Aug 12, 2025
| However, this still runs at 60 fps on an RTX 4070 at 1440p, with most of the time being due to the instance upload CPU bottleneck mentioned above (taking 14 ms of CPU time). | ||
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| Speaking of GPU cost, the scene above renders in about 3.5 ms on the 4070, with ~3.1 ms being spent on the geometry render and ~0.4 ms on the material evaluation. | ||
| After increasing the instance count to over 1 million (almost *900 billion triangles*!), the GPU time increases to about 4.5 ms, with ~4.1 ms on geometry render and material evaluation remaining constant at ~0.4 ms. |
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Add something like "this is X times the triangle count, but only Y more GPU time"
alice-i-cecile
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A-Rendering
SparkyPotato
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JMS55
suggested changes
Aug 12, 2025
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atlv24
reviewed
Aug 13, 2025
atlv24
reviewed
Aug 13, 2025
atlv24
approved these changes
Aug 13, 2025
Co-authored-by: atlv <[email protected]>
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