Troubleshooting

Every issue below has a short cause and fix. The inspector also warns about the most common ones directly under the affected setting.

Nothing shows up

• The renderer feature is missing. The volume override shows an error box with a button that selects the active Universal Render Pipeline asset. Open the Renderer it references and add Global Dirt Render Feature there.
• Intensity is zero. It defaults to zero and the whole effect stays off until you raise it.
• All effects are zero. Raise the Strength of Dirt, Dust or Moss, or one of the variation sliders. Intensity alone does nothing if every effect is at zero, and the inspector says so where the presets are.
• You are looking at the Scene view with Show In Scene View disabled.
• The camera is inside an exclusion zone, or inside a zone whose profile switches everything off.
• Limit To Zones is on and no Global Dirt Zone is in view. The volume inspector warns when the scene has none.

Rust or metal aging does not appear

On Deferred and Deferred+, two things gate both. They need a metallic material: Strength is multiplied by metalness, so a dielectric surface never rusts or ages, no matter how high you push it. And Strength goes up to 2 for exactly that reason, so a half metallic surface can still reach the full effect.

Metal aging has one more gate of its own: it does nothing while both Finish Loss and Discoloration are at zero, because there is then no change to make.

Rust or metal aging covers everything on Forward

Forward and Forward+ have no metalness to read, so there both effects are an approximation that reaches every surface, metal or not. Take their Strength to zero on Forward, or switch the renderer to Deferred or Deferred+ so they only form on metal.

Thickness or Relief do nothing

Dirt Thickness rewrites the surface normal before lighting, which only the GBuffer allows, so it is Deferred only. On Forward the deposits still show, they just stay flat. Moss Relief is the exception: its parallax shifts the moss surface on Standard and High quality, and only the lighting response waits for Deferred. On Fast quality the parallax is dropped as well.

The Cracks controls behave differently on Forward

Cracks come from the material occlusion map, which is available on the Deferred path. On Forward there is no occlusion map to read, so cracks fall back to the side of the surface facing away from the main light. The control still works, it just has less to go on.

Dirt slides over a moving object

The object is not anchored. Add a Global Dirt Object component with Anchor Dirt on, or put the object on a layer listed in Anchor Layers. See Moving Objects & Exclusions.

An excluded object still gets dirty

Layer exclusion needs the object's shader to have a depth and normals pass. All standard URP shaders have one; some custom shaders do not. The inspector flags affected objects under the Excluded Layers setting (it checks each renderer's first material and names up to three examples). A Global Dirt Object with Exclude From Global Dirt does not depend on that pass, so it is the way out for a stubborn shader.

An object profile changes nothing

• The profile has no Global Dirt override. The inspector says so and offers a button to add one.
• No parameter has its override checkbox on. Only checked parameters replace the global value.
• The 16 slots are full. Zone and object profiles share one table; the extras are ignored and named in a warning. Sharing one profile between renderers costs one slot, not one per object.
• The object has its own component. A Global Dirt Object on a child always wins over a parent that includes it.

Unlit objects stay clean on Deferred

That is how Deferred works: unlit and forward-only materials skip the GBuffer. Add their layers to Forward Only Layers to age them too. That extra pass has no GBuffer to read, so those pixels get simplified placement, and metal aging and rust reach them as on Forward, metal or not.

Transparent objects stay clean

Always, on every path. Transparent materials write no depth or normals, so there is no surface for the effect to attach to.

The compare side-by-side mode does not respond

On Deferred, Same Side and Panning work in the Game view only: a hidden camera renders the plain frame, so the scene is drawn twice, fine for comparing but not for shipping. The Scene view and VR cameras on Deferred keep the split line in place. On Forward both work without the extra camera.

A ninth zone does nothing

Up to 8 visible zones are used at once, the highest priority ones. Extra zones are ignored and a warning is logged once.

The override says it lost its data

A volume profile can end up with a stale override after an upgrade. Remove the override from the profile and add it again, or run Tools / Global Dirt / Repair Volume Profiles, which fixes every profile in the project.