Why doesn't my Shader Graph stencil work in URP?

Shader Graph doesn't expose stencil writes directly. URP draws Opaque + Transparent in batched passes; you can override stencil via a Render Objects feature with Stencil State configured.

How do I add a Render Objects feature?

URP Renderer Asset → Add Renderer Feature → Render Objects. Filter by LayerMask. Configure Stencil State (Reference, Compare, Pass operation). Now objects on that layer write the stencil with your settings.

What about reading stencil in a Shader Graph?

Use a Custom Function node + HLSL to sample the stencil texture (URP exposes _CameraStencilTexture in some setups). For complex stencil logic, fall back to a hand-written HLSL shader.

Fix: Unity Shader Graph Stencil Not Writing in URP

Quick answer: Add a Render Objects renderer feature to your URP Renderer. Filter by LayerMask. Configure Stencil State (Reference, Pass = Replace, etc.). Shader Graph itself can’t write stencil; the feature does.

Stencil shader trick (mask out a region, render inside-only) requires writing the stencil. Shader Graph doesn’t expose those toggles. Render Objects feature fills the gap.

The Symptom

Stencil-based effect (portal, mirror, mask) doesn’t mask anything. Either the writer doesn’t set the stencil, or the reader doesn’t respect it.

The Fix

Render Objects feature for stencil writes.

URP Renderer Asset:
  + Render Objects (Mask Writer):
    Render Pass Event: Before Rendering Opaques
    Filter:
      Queue: Opaque
      Layer Mask: MaskGeometry
    Overrides:
      Stencil:
        Override Stencil:    true
        Reference Value:     1
        Compare Function:    Always
        Pass Operation:      Replace
        Fail Operation:      Keep

Objects on the MaskGeometry layer now write 1 to the stencil where they render.

Read the stencil in another feature for the masked rendering.

+ Render Objects (Inside Mask Renderer):
    Filter: Layer Mask: InsideMaskOnly
    Overrides:
      Stencil:
        Override Stencil: true
        Reference Value:  1
        Compare Function: Equal
        Pass Operation:   Keep

Objects render only where stencil = 1.

Verifying

Frame Debugger → Render Objects passes appear in order. Stencil state in the RenderState panel shows your overrides. Final composite shows masked region.

“Render Objects feature owns the stencil. Shader Graph just renders.”

Related Issues

For Renderer Feature blit, see blit pass event. For Render Graph URP 17, see Render Graph URP 17.

Feature writes. Feature reads. Mask works.