Design Nomenclature / Surface & Material

ORM packing

Also called orm, arm packing, rma, channel packing

Storing occlusion, roughness, and metalness in the R, G, and B channels of one texture, since each is a single-channel grayscale quantity and would otherwise waste two thirds of a map. Cuts samplers and memory by three. The channel order is a house convention — ORM, ARM, and RMA are all just labels.

The packed texture at the top, a row of texels in muddy reds and blues captioned as an image of nothing — do not colour-manage it. Below, the same texture exploded into three grayscale strips, arrowed out to the property each one carries: R occlusion dipping through a groove, G roughness wandering, B metalness flipping once from black to white because it is a flag. A boxed warning to the side reads store linear, no sRGB transform.

In practice

Say which order you mean and store it linear, not sRGB. Half the time a material looks wrong the packed map went through a color transform.

Not to be confused with

How this term connects

Ambient occlusionCavity mapCurvature mapDiffuse mapMetalnessRoughnessORM packing
Related Confused with