Errors
| Error | Solution |
|---|---|
| Relocate Unreal Engine without deleting | Move the engine to the new location and edit the path in "%ProgramData%/ |
| Unknown structure on cook | Refresh all nodes of BPs and recompile - or - Make a small change to struct and recompile BPs |
| Infinite loop at construction script | Change "Editorstartupmap" in the "DefaultEngine.ini" to a different map which doesn't contain the looping or crashing BP |
| Your scene contains a skydome mesh with a sky material but it does not cover that part of the screen | Try plugging something/animating(wind) to world position offset |
| Editor resets screen percentage to 66 every launch | Open project settings, go to editor performance and set "Default screen percentage mode for realtime editor viewports." to "Manual or Based on operating system's DPI scale" |
| Degenerate Tangent Bases | Import Normals and Tangents |
| Compiling shaders everytime | Check material flags (used with static lighting etc.) also deleting derived data cache may help |
| Animation won't update on reload | Open your character and select the skeletal mesh. Go to optimization section in the details panel. Set "Visibility Based Anim Tick" to "Always Tick Pose and Refresh Bones" |
| Foliage too thin with MSAA | Multiply opacity mask |
| Render thread crash on exit | Use "Set Enable World Rendering" node first and untick "Enable". Use "Quit Game" node after that |
| More overridden materials on static mesh component than are referenced in source mesh | If you import a mesh object with 6 material ID’s then it’s set as to having 6 materials assigned to it. If you edit the object and lower the number of materials and ID’s to 4 and “re-import” the object your original object is still looking for 6 materials but only 4 are now referenced by the object. To clear the error delete the original instance and import the edited version and and it will now only reference the 4 assigned materials. |
| Slow shader compilation | Change "Shader |
| Launch VR | -vr |
| Launch desktop | -nohmd |
| Exec pin invisible name |
|
| Delay node in macros | Delay node is available in Macro libraries derived from Actor |
| Nearly zero tangents / nearly zero bi-normals | UV problem |
| Unreal can't find file after moving | Delete saved folder |
| Send2Unreal Blender addon error "Could not find an open instance of unreal" | Enable the python script utilities plugin and enable "Enable Remote excecution" in projects settings |
| Can't disable Hololens at supported platforms Hololens enables back at supported platforms | Delete "Hololens" folder from "Platforms" folder in project files |
| Customizing the editor’s toolbar buttons menu via custom plugin | Enable "Display UI extension points" in editor preferences |
| Safe to delete folders | Binaries, Build, Intermediate, Saved, DerivedDataCache After deleting, generate visual studio project files again. Build the project in visual studio again. |
| FSR 3 crash | Instant crouch causes crash with FSR 3 Frame Generation. Use your own crouch logic with timeline, lerp and boolean. |
| Packaged game freeze on exit | Check loops, menu, player. Windows 11 doesn't like windowedfullscreen. Switch to windowed mode. Uncheck borderless window. |
| Physics objects save after simulating | You can press K while simulating the game to save object state (for example last position and rotation of an object after physics simulation). |
| Asset search | Control+P opens asset windows for quick search |
| Resize method | r.SceneRenderTargetResizeMethod - Control the scene render target resize method (This value is only used in game mode and on windowing platforms.) 0: Resize to match requested render size (Default) (Least memory use, can cause stalls when size changes e.g. ScreenPercentage) 1: Fixed to screen resolution 2: Expands to encompass the largest requested render dimension. (Most memory use, least prone to allocation stalls) |
Optimization
| Command | Description |
|---|---|
| stat unit |
|
| stat gpu | GPU |
| stat rhi | CPU render tasks - Draw calls |
| stat game | CPU logic tasks - Ticks |
| stat startfile stat stopfile | For CPU profiling - Records performance metrics Inspect using frontend |
| stat streaming | Textures |
| Ctrl + Shift + , | GPU Profiler |
Drawcalls are much more expensive than triangles
Smaller opacity masks are better for performance
Early Z-pass - Opaque and masked meshes - To reduce overdraw
Meshes: Triangle/Poly Count
Complex shaders/materials cost more when they are closer to the camera (when they take up more screen space)
Tools - Audit - Statistics
r.Tonemapper.GrainQuantization 0 = Minor performance gain
Disable separate translucency if you don't need it
Mask material only in early Z pass - Enabled-to reduce overdraw on masked objects
Enable CSM caching
Check Quad Overdraw and Shader Complexity
Materials
Use Pixel Normal Offset instead of Index of Refraction for large surfaces
Optimization Tips
Keep shader count low
If node calculates both sides
Some nodes are slower than others
Material Blend Modes
https://docs.unrealengine.com/5.0/en-US/material-blend-modes-in-unreal-engine/| Blend Mode | Formula | Description |
|---|---|---|
| Opaque | Final color = Source color | Compatible with lighting. Material will draw on top of the background. |
| Masked | Final color = Source color if OpacityMask > OpacityMaskClipValue | Compatible with lighting. |
| Translucent | Final color = Source color * Opacity + Dest color * (1 - Opacity) | Not compatible with dynamic lighting. |
| Additive | Final color = Source color + Dest color | Not compatible with dynamic lighting. |
| Modulate | Final color = Source color x Dest color | Not compatible with dynamic lighting, or fog, unless this is a decal material. |
| Alpha Composite | Final Color = Source Color + Dest Color * (1 - Source Opacity) | |
| Alpha Holdout | Final Color = Dest Color * (1 - Source Opacity) | Not compatible with dynamic lighting. |
Shading Models
https://docs.unrealengine.com/5.0/en-US/shading-models-in-unreal-engine/| Shading Model | Description |
|---|---|
| Unlit | Emissive Color |
| Lit | Default |
| Subsurface | Simulates subsurface scattering |
| Preintegrated Skin | Cheaper subsurface with less accuracy |
| Clear Coat | Simulates multilayer materials |
| Subsurface Profile | High-end skin rendering |
| Two Sided Foliage | Subsurface scattering for foliage |
| Hair | Simulates multiple specular highlights |
| Cloth | Includes a thin "fuzz" layer across the surface |
| Eye | Simulates the surface of an eye |
| Single Layer Water | Enables to achieve the effect of a transparent water surface while using an Opaque Blend Mode |
| Thin Translucent | Supports physically based translucent Material types |
| From Material Expression | Enables combining multiple shading models into a single material |
Packaging
Max chunk size is in bytes - 1 MB is 1000000 byte
Post process
| Method | Name |
|---|---|
| FXAA | Fast Approximate Anti-Aliasing |
| TAA | Temporal Anti-Aliasing |
| MSAA | Multisample Anti-Aliasing |
| TSR | Temporal Super Resolution |
Nav Mesh at Runtime
Project Settings - Engine Navigation Mesh - Runtime - Runtime Generation: Dynamic
Save
In development platforms, saved game files use the .sav extension and appear in the project's Saved\SaveGames folder
Packaged game in shipping configuration saves to C:\Users\username\
Editor theme location - Engine\Content\Slate\Themes
Streaming Pool Fix
Check texture sizes - Should be power of 2 - Doesn't have to be square (512x1024, 4096x1024)
Check mip gen settings in texture settings
Uncheck never stream in texture settings
Optional (editor related) - Uncheck defer compression in texture settings
Projectile
Make mesh root
GPU Lightmass
Use stationary lighting so you can get dynamic shadows too
Check use area shadows for stationary lights at Directional Light settings
Unlit materials won't bake any shadows
World position offset not supported
Third Person to First Person
Duplicate third person character
Delete camera boom
Attach follow camera to mesh
Parent camera to head bone
Adjust the position and rotation
Set use pawn control rotation to true on camera
Set use controller rotation yaw to true on thirdpersoncharacter
Dynamic Lighting - Deferred
Directional Light - Movable - Atmosphere Sun Light: True
Place Sky Atmosphere
Exponential Height Fog - Start Distance: Max
SkyLight - Movable - Real Tme Capture:True
Post Process Volume - Unbound
Volumetric Cloud
Project Settings - Support Sky Atmosphere Affecting Height Fog: True