Hi John, Glad to hear the DrawMesh API is working out. Looks like this problem might be caused by the projectors. There is a weird behavior of Unity projectors when used together with the DrawMeshInstancedIndirect API - and since it is in the internal Unity code, we don't have access to it. You can try setting GPUI prototypes to a layer and ignore that layer in your projectors - that can actually improve your performance as well. You can take a look at this wiki document; it is about the AQUAS asset's projectors for water caustics, but the idea is the same when using any projector. Please let us know if this solves the issue.