Blockbench + Adobe Substance 3D

Optional and advanced. Most Blockbench work never needs this: paint with blockbench-texturing, generate with blockbench-gpt-image-textures, derive normal/MER with blockbench-albedo-to-pbr. Use this skill only when the user asks for Substance or already has .sbsar/.sbs/Painter assets. It needs a licensed Adobe Substance 3D install. Load blockbench-use first and blockbench-pbr-materials to assign results.

Substance produces image files. Blockbench stays the source of geometry and UVs. Every path ends with files imported through create_texture (data, pbr_channel) or import_texture_set.

0. Locate the tools

python scripts/sat_locate.py

Designer bundles sbsrender, sbscooker, sbsupdater and substance3d_baker, off PATH, in C:\Program Files\Adobe\Adobe Substance 3D Designer\. sbsmutator and the pysbs Python API come only with the standalone Substance Automation Toolkit. Painter is a GUI app driven over HTTP. If nothing is found, stop and tell the user; do not install Adobe software.

Pick the path

Workflow A: procedural material → Blockbench

python scripts/sat_render.py material.sbsar --out out --size 16 --seed 7 \
  --set Season=0.8 --normal-format directx

• --size is pixels; the script converts to log2 $outputsize (raw sbsrender needs '$outputsize@4,4' for 16 px). It creates --out; raw sbsrender exits 47 if the folder is missing.
• Read inputs from the JSON report, then set parameters by identifier. Unknown identifiers come back as warnings, because sbsrender ignores them silently.
• Match outputs to channels by usages: baseColor/diffuse → color; normal; height; metallic + roughness (or glossiness, inverted) + emissive → MER.
• Output is 8-bit by default. Tiling block textures render straight at 16/32 px. For atlases, render at the atlas size or larger and shrink.

Workflow B: bake masks from the Blockbench model

1. Fix UVs: every face needs its own UV rectangle. Default per-face Auto UV on block formats stacks faces on top of each other and ruins the bake. See baker.md § Prepare.
2. export_model → codec_id: "gltf", options: {"encoding": "binary"}, path: <abs>.glb (or obj).
3. Bake at 8–16× density with underscore flags (the online docs show hyphens, which fail):

   substance3d_baker AmbientOcclusion.Raytraced model.glb --use_lowdef_as_highdef true --output_size 512,512 --output_path bake
   

4. python scripts/prep_maps.py convert bake/*.png --out bake/64 --size 64 (16-bit → 8-bit, box downsample).
5. Use the maps as masks: multiply AO into the colour texture, or feed them to sbsrender --set-entry / Painter.

Workflow C: paint in Painter, bring maps back

1. Fix UVs, then export_model with codec_id: "obj". Painter cannot import glTF.
2. Start Painter with --enable-remote-scripting (never --help: it opens the app), then:

   python scripts/painter_remote.py --ping --wait 240
   python scripts/painter_remote.py --python-file scripts/painter_new_project.py --result \
     --set MESH=C:/work/model.obj --set NORMAL=DirectX --set RESOLUTION=1024 --set BAKE=1
   

3. The user paints in Painter (or you script layers after reading the local API docs).
4. Export and shrink:

   python scripts/painter_remote.py --python-file scripts/painter_bedrock_export.py --result \
     --set OUT=C:/work/painter_out --set NAME=model --set PRESET=bedrock --set SIZE_LOG2=9
   python scripts/prep_maps.py convert C:/work/painter_out/model*.png --out final --size 64
   

   bedrock gives NAME.png, NAME_mer.png, NAME_normal.png (DirectX). gltf gives ORM + OpenGL normal. Painter never exports below 128 px, and skips maps whose channel is absent. Trust the files list in the result.

Pack and import

python scripts/prep_maps.py pack-mer --metallic out/m_metallic.png --emissive 0 --roughness out/m_roughness.png --out final/model_mer.png
python scripts/prep_maps.py texture-set --color model --mer model_mer --normal model_normal --out final/model.texture_set.json

Constants are 0–255; --glossiness replaces --roughness and is inverted. Then import_texture_set with the JSON path, or create_texture per file (pbr_channel: color/normal/height/mer) + create_pbr_material. Normal or height, never both.

Conventions and verification

• Normals: Bedrock → DirectX (green-down), glTF/Java labPBR → OpenGL. Baker default is directx. A graph's $normalformat is graph-defined (one tested graph flipped red, not green), so compare renders or use prep_maps.py convert --flip-green. After import, raised features must read as raised in the Blockbench preview.
• 16-bit trap: AO/curvature/height PNGs are often 16-bit; PIL.Image.convert("L") clips them to white. Use prep_maps.py convert or --output-bit-depth 8.
• Paths: pass C:/... paths to the executables; /c/... from Git Bash breaks --alias. Quote '$outputsize@...'.
• Blockbench project safety: note the project UUID before export and import, and confirm it before writing textures back.
• Check each imported map with list_textures/get_texture and a capture_screenshot. A blank-white or uniformly gray map means the bit depth, UV overlap or parameter was wrong. It is not a stylistic result.