Inverted Normal Studio

Sharp Stencil Shadows

Documentation for Sharp Stencil Shadows, a URP renderer feature for hard, pixel-exact stencil shadow volumes.

Known Limitations

Home › Compatibility

Rendering

  • Shadows are hard. There is no soft shadow filtering.
  • Shadows end at the URP asset's Max Distance, without a fade.
  • The 2D Renderer is not supported.
  • On Deferred and Deferred+, Overlay needs a Stencil Mask of 0x0F or less. See Compatibility.
  • Renderers in Tile-Only Mode can't provide scene depth: URP Lighting falls back to Overlay, Textured to Uniform Opacity, and shadows are not fogged.
  • With the default mask in Overlay mode, a caster whose volume stacks a multiple of 8 layers on one pixel loses its shadow there. URP Lighting mode needs 128 layers. See counter wraparound.

Lights

  • Only the main directional light casts stencil shadows in Overlay mode.
  • Point and spot light shadows need URP Lighting, and are limited to 7 per camera.
  • Other directional lights, area lights, and Baked point and spot lights are not shadowed.
  • In URP Lighting, point and spot lights without stencil shadows have no realtime shadows, except on classic Deferred.

See Light type limitations.

Casters

  • An LOD Group's shadow switches level without cross-fading. LODGroup.ForceLOD isn't followed, and billboard levels cast nothing. See LOD groups.
  • Skinned Mesh Renderers drawn at a Mesh LOD level above 0 don't get self-shadow cancellation, and transparent casters draw Mesh LOD level 0 into the caster atlas. See Mesh LOD.
  • Triangles wound backward cast as if they faced the other way, which can leave holes in their shadow. See Mesh Topology.
  • Non-readable meshes loaded only at runtime need the StencilShadowTopology label or registration. Their copies are matched by name, vertex and index counts, and bounds, so two labeled meshes of different shape that share all of these cast no shadow from non-readable copies.
  • A mesh a script edits in place needs ShadowVolumeTopologyRegistration.Refresh, and must be readable in players.
  • Displacement done only in a vertex shader is not visible to shadow volumes.
  • Shadows Only renderers and double-sided or non-depth-writing materials don't get self-shadow cancellation. Vertex-shader displacement can leave part of a caster's self-shadow uncancelled. See Shadows on the casters themselves.

Transparent casters

  • Atlas shadow detail is limited by atlas resolution.
  • In URP Lighting, colored and partial point and spot light shadows need receivers using Sharp Stencil Shadows/Lit.
  • Without Colored Transmittance, the sun's glass shadows in URP Lighting are neutral grey.
  • An off-screen skinned atlas caster keeps its last visible pose unless Update When Offscreen is on.

See Transparent caster limitations.

Receivers

  • Transparent surfaces don't receive shadows.
  • Overlay ignores a material's Receive Shadows setting.
  • In URP Lighting, Unlit and Baked Lit materials receive no shadows.

Cameras and platforms

  • XR, overlay cameras in a camera stack, and preview and reflection cameras are not supported.
  • Deferred renderers don't support MSAA.
  • Platforms other than DX12, DX11, Vulkan, and OpenGL ES on Android are not yet tested. See Compatibility.