Vitruvian Poses

1The problem bending cannot solve

Your rig is a flat, side-on skeleton, so every bone rotates in the same plane as the drawing. That is perfect for a wave or a reach, but it falls apart the moment you need a limb to come toward the viewer, foreshortened, or fold in a way the flat art was never drawn for. Vitruvian poses give one limb a small set of alternative bone-and-art setups, and only one is ever visible at a time. Each setup is a completely different pose for the same arm.

2How it differs from a smart bone

It is easy to confuse this with a smart bone, so hold the difference in mind. A smart bone blends a correction smoothly as a dial turns, so it is for tweaks that ease in and out. A Vitruvian pose is a hard choice: pose A or pose B or pose C, with nothing in between. Because there is no blend, the swap reads as a clean cut on the timeline, which is exactly what you want for a snappy gesture change.

3Start in Rig mode

All the skeleton work happens in Rig mode, the banner mode that edits the rest skeleton and touches nothing on the timeline. Switch to it before you add a single bone, because anything you build here becomes part of the character's default anatomy rather than a keyed pose. If the banner shows Animate mode or Test mode, click back to Rig mode first. You want a calm, timeline-free workspace while you lay out the alternatives.

4Build the first alternative: the straight arm

Grab Add Bone and lay in your baseline pose, the ordinary straight-down arm, dragging from the shoulder to the elbow and then elbow to wrist so the second bone parents to the first. This is the arm the character wears most of the time, so build it cleanly and name the bones in the Bones panel Name field (something like arm-straight-upper). Keep the chain tidy, because you are about to build two more chains in the same space. This first set is your fallback pose.

5Build the bent and raised alternatives

Now add two more arm chains in the same shoulder area with Add Bone: one folded into a bent elbow, and one raised so the hand comes forward toward the camera. These are full alternatives, not just rotations of the first, so give each its own bones and its own artwork on separate points or sub-layers. Name them clearly (arm-bent, arm-raised) in the Bones panel. At this stage the stage looks a mess with three arms overlapping; that is expected and about to be cleaned up.

6Bind each alternative to its own bones

For the swap to look clean, each alternative's artwork must move with only its own bones. Select the points that belong to the raised arm and use Bind Points to lock them to that chain, or Flexi Bind if you want the points to flow smoothly along the chain instead of snapping to the nearest bone. Repeat for the bent arm and the straight arm. If you skip this, hiding one pose will drag the wrong points around and the whole thing will look broken.

7Open the Vitruvian poses panel

With all three chains built and bound, open the Vitruvian poses panel. This is where you tell the rig that these separate chains are actually one limb with different poses. The panel lists your bones with a tick box beside each, and a grouping button that reads Group (pick 2+) until you have selected at least two. Nothing has changed on the stage yet; you are just about to declare the relationship.

8Tick the alternatives, then group them

Tick the box next to each bone that represents an alternative of the same limb, so the straight, bent, and raised upper-arm bones all get a tick. As soon as two or more are ticked, the button changes from Group (pick 2+) to Group N bones, showing your count. Click it, and the panel creates a new group row labelled #1 with the members joined by a slash, so you might see arm-straight / arm-bent / arm-raised. That single row is now your limb, and only one of its members will show at a time.

9The Active pose picker on the stage

Look at the stage: there is now an Active pose picker for your group (its options read Pose 1, Pose 2, Pose 3, one per member in order). This little control is how you choose which alternative is visible right now. Flip it and watch the arm snap from straight to bent to raised. The picker order follows the order the bones sit in the group row, so Pose 1 is your first ticked member.

10It keys, so the swap animates

Now the payoff. Switch to Animate mode, turn on Auto-key, move the playhead to the frame where the gesture should change, and pick a new option in the Active pose picker. The choice lands as a keyframe at that frame, so during playback the arm holds one pose and then cuts to the next exactly when you asked. Because a Vitruvian swap is a discrete choice, it does not tween; it pops on the frame you keyed, which is perfect for a sharp accent.

11Worked example: the arm that points at you

This is the classic case that bending can never fake. Your straight and bent arms sit in the flat side-on plane, but the raised alternative was drawn foreshortened, with the hand large and the forearm short, so it reads as pointing out of the screen. Set the playhead to the punchline frame, pick the raised Pose, and the arm jumps out at the reader. No bone rotation on Earth would have produced that; you needed a genuinely different drawing, and Vitruvian poses let you hold it in the same rig.

12More than one group per character

A character can carry several Vitruvian groups at once: one for each arm, one for each leg, even one for a head that turns to a three-quarter view. Build each set of alternatives, tick its members, and click Group N bones again to create #2, #3, and so on. Every group gets its own Active pose picker on the stage, so you can drive the left and right arms independently. Keep your bone names descriptive, because with two arms and two legs the panel fills up fast.

13Editing and deleting a group

Changed your mind about a group? In the Vitruvian poses panel each row carries a Delete Vitruvian group control, which dissolves the grouping and returns the bones to being ordinary, separately visible chains again. Deleting the group does not delete the bones or the art; it just removes the one-at-a-time relationship. If you want to add a fourth alternative later, build the new chain, tick it alongside the existing members, and regroup. Treat the group as a lightweight label over your bones, not a cage.

14What good looks like

A well-built Vitruvian limb feels invisible: the reader never notices three arms exist, they just see one arm doing something impossible. The tells of a good setup are clean binds (no stray points twitching when you switch), sensible names, and swaps that land on story beats rather than at random. Play the animation at full speed and watch only the shoulder join; if the transition reads as a deliberate accent and not a glitch, you have nailed it. If it reads as a flicker, move the key to a stronger beat or add a held frame on either side.

Quick questions