# \[PCG GPU\] Removed Points Still Counted in GPU Scene Instance Count 

**URL:** <https://forums.unrealengine.com/t/pcg-gpu-removed-points-still-counted-in-gpu-scene-instance-count/2853851>\
**Category:** Rendering\
**Tags:** unreal-engine, Epic-Pro-Support, question\
**Created:** [October 8, 2026, 1:20pm UTC](https://forums.unrealengine.com/t/pcg-gpu-removed-points-still-counted-in-gpu-scene-instance-count/2853851 "2026-10-08T13:20:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![anonymous-edc](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous-edc](https://forums.unrealengine.com/u/anonymous-edc)\
**Post date:** [October 8, 2026, 1:20pm UTC](https://forums.unrealengine.com/t/pcg-gpu-removed-points-still-counted-in-gpu-scene-instance-count/2853851/1 "2026-10-08T13:20:14Z")

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I wanted to ask whether the following behavior is intended when using GPU point culling together with the GPU Static Mesh Spawner.

I start with **5,000 points** and remove **2,000 points** using a custom HLSL node on the GPU or the **Cull Points Outside Actor Bounds (GPU)** node. This leaves **3,000 points** , which are correctly rendered when passed to a GPU Static Mesh Spawner.

However, the resulting PCGProceduralISMComponent still reports **5,000 instances** in the Details panel, and the GPU Scene also appears to register 5,000 instances. Interestingly, this behavior changes depending on the Mesh Selector Type:

- With PCGMeshSelectorWeighted :5,000 instances are reported in the PCGProceduralISMComponent.
- The GPU Scene also appears to contain 5,000 instances.
- Only the remaining 3,000 points are actually rendered.
- With PCGMeshSelectorByAttribute: The PCGProceduralISMComponent correctly reports 3,000 instances.
- The GPU Scene also appears to contain the correct 3,000 instances.

This seems somewhat counterintuitive to me, especially when looking at the comment in PCGStaticMeshSpawner.ucf:

```auto
// Static mesh spawner kernel. Selects a primitive either using a primitive cumulative distribution function (CDF) or by an attribute, and packs attributes in custom floats.
// Passes through points to output.
 
// When spawning by attribute, we don't know in advance how many instances of each mesh will be spawned, so the worst case NumPoints * NumPrims is allocated in the GPU Scene.

```

Based on this comment, I would have expected PCGMeshSelectorByAttribute to potentially allocate more instances, rather than PCGMeshSelectorWeighted retaining the original point count. So my questions are:

1. Is it expected that GPU-culling points does not reduce the allocated/registered instance count when using PCGMeshSelectorWeighted?
2. Is the difference between PCGMeshSelectorWeighted and PCGMeshSelectorByAttribute intentional?
3. Is there something conceptually incorrect about my setup or understanding of how GPU-culling and the GPU Static Mesh Spawner interact?
4. If the GPU Scene still contains the original 5,000 instances in the Weighted case, does that have any performance/memory implications, even though only 3,000 instances are ultimately rendered?

I would appreciate some clarification on whether this is intended behavior or potentially an issue with the GPU Static Mesh Spawner.

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**Author:** ![anonymous-edc](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous-edc](https://forums.unrealengine.com/u/anonymous-edc)\
**Post date:** [October 8, 2026, 1:20pm UTC](https://forums.unrealengine.com/t/pcg-gpu-removed-points-still-counted-in-gpu-scene-instance-count/2853851/2 "2026-10-08T13:20:18Z")

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**Steps to Reproduce** [Attachment Removed]

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**Author:** ![anonymous-edc](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous-edc](https://forums.unrealengine.com/u/anonymous-edc)\
**Post date:** [October 23, 2026, 8:43am UTC](https://forums.unrealengine.com/t/pcg-gpu-removed-points-still-counted-in-gpu-scene-instance-count/2853851/3 "2026-10-23T08:43:17Z")

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Thank you! This answers all my questions perfectly.

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