This section describes which types of motion different shaderA program that runs on the GPU. More info
See in Glossary types support for calculating motion vectors.
URP supports motion vectors only for opaque materials, including alpha-clipped materials. URP does not support motion vectors for transparent materials.
URP Lit, Unlit, Simple Lit, Complex Lit, and Baked Lit shaders support per-object motion vectors for the following motion types:
To enable alembic motion vectors for particular material, enable the Alembic Motion Vectors checkbox in the Advanced section of the material inspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary.
Note:: Use materials with the Alembic Motion Vectors checkbox enabled only on alembic vertex animation caches rendered with a PlayableDirectors component. When using such materials with regular draw calls and MeshRenderers, the materials cannot read the correct motion vector attribute stream, which results in incorrect motion vectors.
The URP Shader Graph Lit and Unlit targets support all of the motion vector features described in the URP ShaderLab shaders section. In addition to that, they have the Additional Motion Vectors setting with the following options:
Time-Based: motion vectors for a Shader Graph vertex animation are generated automatically by running the vertex position subgraph twice with the current and the previous frame values for the Time node. This mode only works correctly for vertex animations that are computed procedurally based on the Time node, and that use only user-defined parameters (constants, attributes, buffers, textures) that do not change between frames.
Custom: selecting this option adds an extra Motion Vector vertex output. The output lets you specify a custom object motion vector: a 3D local object space offset for each vertex from where it was in the previous frame. If you know how to compute the position of a vertex in the previous frame, you can author custom motion vectors for your vertex animations. Unity applies the custom motion vectors additively to transform motion, skeletal animation, and alembic animation before projecting the motion vector to the final 2D screen space vector.
None: the default value. Use this option when the shader either does not modify the vertex output or if it does not animate the vertex deformation.
The options Time-Based and Custom enable the MotionVectors pass on the materials. The object motion vector pass is rendered every frame for them, even when the object’s transform is stationary between frames, unless the MotionVectorGenerationMode property is set to Camera.