Troubleshooting

On this page you can find information about important things related to the GPU scattering and how to troubleshoot what is going on.

• If meshes are generated in the viewport but fail to generate during gameplay, make sure to have the consol variable enabled in order to spawn objects at runtime during the gameplay:

grass.GrassMap.AlwaysBuildRuntimeGenerationResources 1

• If your system path to UnrealEngine contains non english laters, the generation problem should be fixed in v3.11.

HOWEVER, if you still experience problems, try these steps first:

1. Corrupted or partial engine install. Inside of the EpicLauncher, push the arrow next to the installed engine version and click: "Verify". This re-downloads any missing or mismatched engine files. 

2. Stale DDC / ShaderAutogen cache. Try cleaning the cache, sometimes the engine fails to see any changes and forces cached compilers. Clear: 

3. <Project>/Saved/ShaderDebugInfo

4. <Project>/Intermediate/ShaderAutogen

5. <Project>/DerivedDataCache

6. %LOCALAPPDATA%\UnrealEngine\Common\DerivedDataCache

7. Sometimes, the engine fails to enable the GPU related framework. Go to Edit>Plugins and search for "Compute Framework" plugin.

8. RHI / shader model. PCG GPU compute kernels require SM6 / D3D12. Check Project Settings > Platforms > Windows > Default RHI is set to DirectX 12 and shading model is set to SM6.

9. GPU driver. PCG GPU compute is sensitive to shader compiler bugs in older drivers. If you are on a notably old NVIDIA or AMD driver, please update them.

10. Path length / non-ASCII in project path. If your project sits at something like D:\我的项目\PCGTest\ or any path with non-ASCII characters, multibyte spaces, or that exceeds Windows' 260-character path limit, the shader compiler subprocess can fail to read/write ComputeKernel.ush correctly. 

If non of these work, please write me an email stating "ForestTools GPU failure", specify your engine version and what you receive in Unreal Engine LOG (Just copy paste everything from when you first dropped the GPU actor into the scene). It might also help to open the PCG graph inside the actor and screenshot any red errors that might be there.