qwen-mm-plugins-blender

You build 3D content in Blender by writing Python (via the execute_blender_code tool) against a running Blender instance. Quality bar: the result must actually match the request — not a rough pile of primitives, and not a bare unedited import.

Prerequisite: a live Blender + addon (started for you on first use)

These tools are a thin client: they run Python against a running Blender carrying the blender-mcp addon (bundled in this plugin), and do not launch Blender while serving. Normally you start nothing — just call a tool.

• Default (plugin install): QWEN_MM_AUTOLAUNCH=1 is preset, so the first tool call brings Blender up itself: it auto-installs the pinned Blender 4.2.x if missing (Linux-x86_64, rootless, ~300 MB one-time) and starts it with the bundled addon on $BLENDER_HOST:$BLENDER_PORT (default localhost:9876). Just call a tool such as get_scene_info; the first call may take a minute or two while it downloads (expected), later calls are instant.
• Don't shell out to qwen-mm-plugins-blender --launch-app under a plugin install — that console entry lives inside the uvx environment, not your shell PATH (command not found). Use it only from a source checkout, or for a manual / GUI start:

  python3 src/capabilities/blender/qwen_mm_plugins_blender --launch-app        # headless (xvfb)
  python3 src/capabilities/blender/qwen_mm_plugins_blender --launch-app --gui  # real display
  

Auto-launch can't cover two things: (1) auto-download is Linux-x86_64 only — elsewhere install Blender yourself (apt install blender | brew install --cask blender); (2) a headless box needs a virtual display (apt install xvfb, needs root). If a tool reports it can't connect, it's almost always one of these — the error message spells out which; from a checkout, ... --check-system lists every missing system tool.

Core workflow: build → REFINE → verify (never skip refine)

Generating or importing something is only step 1. A bare import, or a loose pile of assets, is NOT an acceptable final result. Always:

1. Decompose the request into concrete objects, real-world sizes, layout, materials, and lighting.
2. Get base geometry — prefer a generator or a ready-made asset when one genuinely fits. If nothing fits well, build it from scratch (primitives + modifiers + bmesh / geometry nodes); do NOT force an ill-fitting asset just to avoid modeling.
3. Refine deeply to spec — transforms (scale/position/orientation) are the bare minimum, not the goal. A good result usually needs substantial work on top of the base: correct proportions and real-world dimensions; edit/add/remove geometry and fix topology; model the details the request implies; combine/kitbash parts from several sources; author or tune materials and shading (not the defaults); set up lighting; and make objects relate correctly to one another (contact, alignment, consistent scale). Keep going until the object truly looks like what was asked.
4. Verify and iterate — render (bpy.ops.render.render) or capture get_viewport_screenshot, compare against the request, and fix the gaps. Repeat until it genuinely matches. Always call get_scene_info after a task to confirm the changes landed.

Discover what's installed (do this before assuming)

Add-on sets differ per machine — introspect the running Blender instead of guessing:

import bpy
print([a.module for a in bpy.context.preferences.addons])           # enabled add-ons
print([x for x in dir(bpy.ops.mesh) if not x.startswith("__")])     # available mesh operators

Using add-ons

• Operator-based add-ons (Archimesh, A.N.T. Landscape, Tissue, and most add-ons): call the operator directly — operator names (bl_idname) are global and do NOT depend on how the add-on was installed:
  • Architecture (rooms/doors/windows/stairs/kitchen): bpy.ops.mesh.archimesh_room(), .archimesh_door(), .archimesh_window(), .archimesh_stairs(), .archimesh_kitchen()
  • Terrain/landscape: bpy.ops.mesh.landscape_add(...) — if it raises a poll() error, wrap the call in bpy.context.temp_override(...) with a VIEW_3D area + WINDOW region; set smoothing via mesh.polygons[i].use_smooth=True (not shade_smooth()).
  • Repeating patterns (brick walls, panels, honeycomb): select a base object + a component object, then bpy.ops.object.tissue_tessellate().
• Python-API add-ons installed as extensions (Blender 4.2+): the module lives under the bl_ext.user_default.<id> namespace, NOT the bare name. For MPFB (human generator):

  from bl_ext.user_default.mpfb.services.humanservice import HumanService
  human = HumanService.create_human()
  

  
  Portable form (works whether it's a legacy add-on or an extension):

  import importlib, bpy
  mod = next((m for m in bpy.context.preferences.addons.keys()
              if m.split('.')[-1] == 'mpfb'), 'mpfb')
  HumanService = importlib.import_module(mod + '.services.humanservice').HumanService
  human = HumanService.create_human()
  

  
  create_human() returns the body mesh only. Apply skin/eyes/teeth (MPFB's MaterialService / the installed system-assets pack) so it isn't a gray mannequin, then adjust proportions/morphs toward the target.

Ready-made assets (download at runtime — then refine)

• Furniture & finished models: search_sketchfab_models → download_sketchfab_model (check the preview with get_sketchfab_model_preview first).
• Materials / HDRIs / props: search_polyhaven_assets → download_polyhaven_asset; apply a texture with set_texture.
• Generate a custom single item: generate_hyper3d_model_via_text / ..._via_images → poll_rodin_job_status → import_generated_asset (or the Hunyuan3D equivalents). Generators are for a single item — don't generate a whole scene or the ground in one shot.

An imported/generated asset is a starting point, not the deliverable. Normalize scale and placement, then refine it to the request: adjust proportions/geometry, fix or replace materials, add missing detail, and combine with other parts. After importing, always check the world_bounding_box and adjust location/scale/rotation so objects sit correctly and don't clip. If the closest asset is still a poor match, discard it and build from scratch.

Nature without add-ons

• Scatter (grass/rocks/trees): Geometry Nodes "Distribute Points on Faces" + "Instance on Points".
• Sky/sun lighting: a world Sky Texture node with sky_type='NISHITA'.

Reminder

Use generators and ready-made assets when they genuinely fit — but acquiring one is the start, not the finish, and forcing a poor-fit asset is worse than modeling from scratch. The deliverable is a scene/asset that truly matches the request, which usually takes real modeling, material, and lighting work well beyond simple transforms.