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Part of the text-to-motion skill. The skill links here when your agent needs the detail.
The motion model reads the skeleton’s rest pose, hierarchy and bone names. Names carry meaning: a bone called LeftArm borrows everything the model learned from human arms. Rigs named like a human skeleton therefore animate far better than freeform names, even on non-humans. Measured on cartoon flowers: with plant names (Stem1, LeafL1) most prompts barely moved; the same rig with human names nodded, bowed, gestured and looked around on cue.

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Limits the service enforces

  • One skinned armature driving the mesh; GLB or FBX; at most 100 MB.
  • 5-70 bones total (helper, twist and finger bones count). Remove extras before submitting.
  • Existing animations are ignored; the service adds its own reference clip.
  • Facing is detected from a left/right limb pair (RightUpLeg/LeftUpLeg, else arms).

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Humanoids

Meshy, Mixamo-style (mixamorig:*) and Summer auto-rig skeletons work as-is. Summer character packages (character-model) can use text-to-motion for extra custom clips; keep the package’s canonical idle/walk/run/jump from generate-motion.

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Non-humanoids: map the body plan to human bone names

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Talking-flower recipe (validated)

  • Stem = Hips > Spine > Spine1 > Spine2 > Neck > Head; petals parented to Head.
  • Leaf-arms on the upper-middle stem, parented to Spine1/Spine2, pointing sideways.
  • Keep the arms clear of the petals and face. Hands that touch the lower petals get their weights mixed and the mesh warps when the arm moves; arms lower on the stem deform cleanly.
  • Submit with lockJoints: ["Hips","Spine"] so the flower stays planted, and cfgScale: 5 for readable gestures.

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Rigging an unrigged mesh

  • Humanoid: the Summer auto-rig (character-model, assets.generate_3d with rig: true).
  • Other body plans: rig in the user’s own Blender (fabricating-assets) or offline (skintokens-auto-rigging), using the human bone names above where the body plan allows (stem as spine, leaves as arms).
Check the weights around every joint that will move before animating. A rig with bad weights produces bad clips regardless of the motion; mesh warping at a joint is a rig problem, not a motion problem.
Source: library/skills/text-to-motion/rigging-for-text-motion.md, rendered from summer-engine@4.3.0 on npm.