Proscenium for Blender

The officially supported MMCP client for Blender 4.x. Sketch poses on an armature, draw a path on the floor, pin a hand to an empty — click Generate, get a glTF animation baked straight onto your rig.

The addon doesn't ship a model. It speaks plain MMCP HTTP to whatever MMCP-compatible server you point it at — a self-hosted motionmcp-kimodo on your workstation, or the hosted Animatica Cloud product.

Install

Option 1 — install the zip (recommended for users)

git clone https://github.com/animatica-ai/proscenium-blender
cd proscenium-blender
make zip
# → dist/proscenium-blender-X.Y.Z.zip

In Blender:

1. Edit → Preferences → Add-ons → Install…
2. Pick the dist/proscenium-blender-X.Y.Z.zip.
3. Tick Proscenium — AI Motion Generation in the addon list.

Option 2 — symlink the source tree (for development)

make install

Symlinks proscenium_blender/ into your Blender 4.x addons directory (~/Library/Application Support/Blender/4.2/scripts/addons on macOS; override BLENDER_ADDONS_DIR for other paths). Editing files here lands live in Blender on the next addon reload.

make uninstall removes the symlink.

Configure

Once installed and enabled:

1. Edit → Preferences → Add-ons → Proscenium → Preferences
2. Set Server to your MMCP endpoint:
   • Self-host: http://localhost:8000 (default)
   • LAN GPU box: http://your-box.lan:8000
   • Cloud: whatever URL the hosted product gives you

That's it — the addon discovers the available models via /capabilities.

Use

1. Open the N sidebar in the 3D viewport, pick the Proscenium tab.
2. Connection panel → click Connect. Pick a model.
3. Import <model> skeleton — adds a Blender armature that mirrors the model's canonical skeleton.
4. Main panel → set the target armature.
5. Add prompt blocks on the timeline, draw root paths, pin effectors — whatever direction you want to give.
6. Click Generate Motion. The addon POSTs to /generate, parses the returned glTF, bakes joint rotations + the root translation onto your armature as a fresh action.
7. Accept keeps the result; Reject reverts.

For a single keyframed pose at the current frame (non-destructive, undo-able), use Generate Pose @ Frame N instead.

Architecture

File	Role
mmcp_client.py	stdlib HTTP client, capabilities cache, MmcpError
canonical_skeleton.py	Import operator: build a Blender armature from the model's canonical_skeleton
coords.py	MMCP (right-handed Y-up) ↔ Blender (right-handed Z-up) axis swap + quaternion remap
request_builder.py	Assembles a complete GenerateRequest (segments + constraints + options) from current Blender state
constraints_ui.py	Operators + scene-walker + samplers for root_path curves and effector_target empties
gltf_to_blender.py	Decodes the data:-URI buffers in the glTF response and writes pose-bone keyframes
mixamo_bake.py	Optional bake step for control-rig-style armatures (e.g. Mixamo Control Rig)
operators.py	proscenium.connect, proscenium.generate, proscenium.generate_pose, proscenium.accept / reject / cancel
panels.py	Sidebar panels: Connection, Main, Constraints, Settings
path_follow.py	Path-curve constraint helpers for the Proscenium root-path workflow
timeline_operators.py + timeline_overlay.py	Prompt-block strips on the dopesheet (drag, resize, inline edit, hatched fill for unconditioned spans)
properties.py	ProsceniumSettings, PromptBlock, addon preferences

The addon is ML-free: all generation, retargeting, and post-processing happens on the server.

Protocol & spec

The MMCP wire format is documented at animatica.ai/mmcp. The addon implements the client side — capabilities discovery, request assembly, glTF response decoding. If you'd rather build your own client, the Quickstart (client) walks through it.

Compatibility

• Blender 4.x (tested on 4.2 LTS through 4.4).
• MMCP v1.0 wire format. Designed to keep working against any v1.x server thanks to additive minor versions; see Versioning.
• The addon ships no Python deps beyond Blender's bundled stdlib — urllib, json, base64. No pip install step inside Blender.

Limitations (current)

• Server-side retargeting required when your rig doesn't match the model's canonical skeleton. Self-hosted motionmcp-kimodo doesn't support retargeting yet — use Import canonical skeleton in the addon, or point at the cloud.
• One sample per request. Multi-sample picker is future work.
• No async polling. The addon waits synchronously on /generate.

License

GPL-3.0-or-later — see LICENSE.

Blender itself is GPL-2.0+, and the Blender Foundation considers addons that import bpy to be derivative works of Blender. GPL-3.0+ keeps distribution clean across the Blender Extensions Platform and the wider addon ecosystem. The MMCP protocol and the motionmcp SDK that this addon talks to are Apache 2.0 — neither imports bpy, so the GPL boundary stops at the addon.