Surface Assign Material

Overview

Assigns a material ID to part of a Surface using a mask image. Only white or opaque areas can be changed to values such as core:metal or core:emissive.

This node does not directly change visible color. It paints information used by downstream lighting and future material processing to identify areas such as metal or emissive material.

Usage tips

• The effect appears downstream. Nothing changes visibly immediately after painting; differences appear in nodes that inspect materials, such as surface_light_preview.
• Its main use is for parts with a distinct material, such as a sword blade, lamp, or window.
• Use the general-purpose surface_assign_id when both material and face IDs are needed.

Related nodes

• surface_assign_id — general version that also paints face IDs
• surface_id_mask — extracts the painted material region
• surface_light_preview — reviews the material effect
• solid_set_material — assigns a material at the solid stage

Examples

• Create a mask for a sword blade and paint material_id=core:metal.
• Create a mask for a lamp and paint material_id=core:emissive.
• Mark only dirty areas of a brick wall as core:dirt for easier future material processing.