Unreal Engine Issues

Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled

When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...

Pass names appear as "RDGEvent" in Unreal Insights when r.rhisetgpucaptureoptions=1

When capturing a trace in Unreal Insights, all r.rhisetgpucaptureoptions=1 (r.RDG.Events=3) all RDG pass events appear simply as RDGEvent, without the actual name due to the logic for RDG_EVENT_SCOP ...

Placed render targets are not initialized properly in D3D12

Virtual Texture Collection Indexing Not Working

Textures at an index, other than 0, cannot be sampled from a Virtual Texture Collection in a material. When using the Texture Collection and Texture Object From Collection material nodes, with a Vir ...

HZB Occlusion causes large stalls on the render thread

HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...

The Console Command list printed by using "Help" misses alot items in 5.6

FD3D12BindlessResourceManager::GrowCPUHeap will cause GPU heap activation whether it's needed or not

The ctor of FD3D12BindlessResourceManager implies that GPU heap activation is intended to occur lazily with ERHIBindlessConfiguration::RayTracingShaders, however any call to FD3D12BindlessResourceMa ...

Enabling STATS causes RenderThread to wait for GPU

The licensee noticed that in Development builds, the Render thread times are suspiciously similar to GPU times, and the same thing happens when enabling FORCE_USE_STATS in Test configuration. The is ...

Missing PSO Precaches in the engine

A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...

Performance slowdown when ray tracing is disabled due to SetResidencyPriority

When a game is compiled with ray tracing disabled (D3D12_RHI_RAYTRACING=0) and the GPU the game is running on becomes low on VRAM, frame time is negatively impacted and doesn't recover. The D3D12_RH ...