Materials

A material defines how a surface looks: its color, how shiny or rough it is, whether it glows, and more. You author materials in a visual node graph, no shader code required.

The three asset types

Asset	What it is
Material	A node graph that compiles to a shader. The real thing a surface is drawn with.
Material Instance	A lightweight variant of a Material that only changes its parameters (colors, numbers, textures).
Material Function	A reusable group of nodes you can drop into many materials.

A material is a compiled shader

This one idea shapes everything else. When you author a Material, the engine compiles its graph into a shader. At render time the engine groups objects by material into draw buckets, one bucket per unique Material, and draws each bucket together.

So every unique Material costs a shader to compile and a bucket to draw. Two hundred distinct Materials means two hundred shaders and two hundred buckets, that is the budget you manage.

The golden rule

Make a handful of Materials, then create a Material Instance for each variation. An instance reuses its parent’s shader and draws in the same bucket, it only swaps parameter values, so it adds neither a shader nor a bucket. See Material Instances.

Assigning a material

A mesh has one or more material slots, one per surface. Assign a material to a slot in the mesh’s editor, or override it per entity with the mesh component’s Material Overrides in the Details panel. A slot accepts either a Material or a Material Instance.

In this section

• The Material Graph, authoring a material with nodes.
• Material Instances, cheap variations of a material.
• Best Practices, keeping materials fast.