How it works:

Before installing! This addon is verified to work only in Blender 5.1  and support for older version will not be provided.

Setup: Select a mesh object with a UV map and switch to Texture Paint mode. Open the N-panel and find the PaintStack tab. Click "Initialize PaintStack Material" to set up a node-based material on your object.

Adding layers: Use the + buttons in each section to create layers:
Masked layers include both a color image and a grayscale mask image. Toggle between painting color and mask with the edit target buttons. When editing masks, your brush automatically switches to grayscale mode.
Transparent layers use a single RGBA image. Toggle between Paint and Erase modes to add or remove alpha.
Bump layers store height information for normal map generation.
Roughness and Subsurface layers paint directly to their respective material channels.

Painting: Select a layer from the stack to make it active. The corresponding texture node is automatically selected in the shader editor, and Blender's canvas is set to that layer's image. A colored banner at the top of the viewport shows which layer type and target you're currently editing.

Behind the scenes: PaintStack automatically builds and maintains the shader node tree. Each layer gets prefixed texture nodes (PS_L0_Color, PS_L0_Mask, etc.) that feed into mix nodes with your chosen blend mode and opacity. Bump layers connect through Bump nodes to the Principled BSDF's Normal input. When you reorder layers or change settings, the node tree rebuilds to match.

Resolution: Choose 1K, 2K, 4K, or 8K when creating new layers. Each layer can have a different resolution. Existing layers keep their resolution if you change the setting later.

Persistence: All layer images are packed into the .blend file with fake user flags. When you save and reopen your project, PaintStack rebuilds the node tree from your saved layer data. No external image files are required.

Export: When you're ready to bake, set your export resolution and output directory. PaintStack composites visible layers using NumPy, applying your blend modes and opacity settings. It generates standard PBR maps (albedo, normal, height, roughness, subsurface) that you can use in any renderer or game engine.

Note on baking: PaintStack uses fast, direct pixel compositing with simple mathematical calculations. This provides quick exports that closely match your layer stack, but the output may not be 100% identical to a full procedural material bake from Blender's cycles/EEVEE renderer. PaintStack is primarily designed for layer-based texture painting—the bake feature is a convenience tool for export. For production-grade baking with complex procedural materials, consider using dedicated baking addons or Blender's native bake system.