Texture Channel Packer

Free built-in utility to merge Metallic, Smoothness, AO, and Height into a single RGBA map for maximum VRAM efficiency.

What is the Texture Channel Packer?

The Texture Channel Packer is a free utility bundled with OptiDraw (and available separately) that merges up to four grayscale texture maps into a single RGBA texture. This is the standard technique used in AAA pipelines to pack Metallic (R), Ambient Occlusion (G), Detail Mask (B), and Smoothness (A) into one texture — commonly called a Mask Map (HDRP) or MADS map.

Texture Channel Packer Window Layout & Channel Slots

Packing 4 grayscale maps into one RGBA texture reduces your texture memory by 4× compared to keeping them separate. On a 2K texture, that's ~16 MB → ~4 MB.

Opening the Packer

1Window → OptiDraw → Texture Channel Packer
2Drag your source textures into the R, G, B, A slots
3Set output resolution and format (PNG, EXR, or TGA)
4Click Pack & Export — the output texture is saved to your chosen folder and auto-imported

Interactive Tag Inspector (12 items)

Tag [A]

Packing Workflow: RGBA Channel Mapping, Invert Toggles, and Export Presets

ADrag & Drop Texture Area

1 / 12

Quickly add up to 4 textures by dragging them directly into this zone.

Common Packing Presets

HDRP Mask Map: R = Metallic, G = AO, B = Detail Mask, A = Smoothness
URP MetallicSmoothness: R = Metallic, A = Smoothness (GB unused / white)
Custom Vertex Weight: pack any 4 grayscale data maps for use in Shader Graph

Invert Channel

Each channel slot has an Invert toggle. Use this to convert Roughness → Smoothness (invert A) without pre-processing the source texture in an external tool.