Using Video Mocap in Blender — Import, Clean Up, and Retarget BVH

You have a BVH file, captured from video or downloaded from a mocap library, and a character in Blender that you want to perform it. The pipeline is import, inspect, clean, retarget. Each step has one or two settings that make the difference between an afternoon of progress and an afternoon of confusion, and this guide walks through them in order.

Importing the BVH

File → Import → Motion Capture (.bvh). Blender creates a new armature named after the file, with one bone per joint and keyframes on every frame. Three import options matter. Scale: BVH files from different sources use different units (ours exports centimeters); if the skeleton imports tiny or gigantic, reimport with scale 0.01 or 100 rather than scaling the object afterwards, so the root motion curves stay in sane units. Frame Start 1 keeps the action aligned with your timeline. And leave 'Update Scene FPS' checked, or set the scene frame rate yourself to match the file, because a 30 fps capture played at 24 fps runs 25% slow.

Inspect Before You Edit

Scrub the whole clip once in the viewport before touching anything. You are looking for three kinds of defect: pops (a joint snaps for one or two frames, typical where tracking briefly failed), sliding (feet drift during frames where the tracker interpolated a gap), and flips (a limb rotates the long way around between frames). Note the frame ranges. It is faster to fix known ranges than to hunt problems while editing.

Cleaning in the Graph Editor

Select the misbehaving bone, open the Graph Editor, and look at its rotation curves. Pops show up as single-frame spikes: box-select the spike keys and delete them; Blender interpolates across the hole. Residual jitter responds to Key → Smooth Keys, or for stronger control add a Smooth modifier to the curve. Flips appear as a curve jumping ±360 degrees; select the keys after the jump and use the Discontinuity (Euler) Filter, which exists precisely for this. Work on copies: duplicate the action in the Action Editor first, so you can always A/B against the raw capture.

Retargeting Onto Your Character

The imported armature is not your character's rig, so the motion has to be transferred. Three routes, in increasing order of setup effort. Constraints by hand: add a Copy Rotation constraint to each of your rig's deform bones targeting the corresponding BVH bone, set constraints to World space, then bake (Object → Animation → Bake Action) and delete the constraints. Tedious but dependency-free, and fine for a 16-joint skeleton. Auto-Rig Pro's Remap tool: paid addon, maps bone names between skeletons once, then retargets any clip in two clicks; worth it if you do this regularly. Rokoko Studio Live (free addon): includes a retargeter with automatic bone mapping that handles most humanoid rigs.

Whatever route you take, match rest poses first. If the BVH skeleton is in T-pose and your character rests in A-pose, rotate your character's arms to a T and apply that as the new rest pose before retargeting, or every arm rotation arrives with a constant offset.

Root Motion and Feet

Video-derived mocap stays roughly in place: the pose is right but world travel is not reconstructed. For a walk, add the forward motion yourself: keyframe the armature object (not the root bone) moving forward at the pace the feet imply, and the in-place cycle reads as locomotion. Foot sliding that survives cleanup is best fixed with temporary IK: add IK constraints to the feet, keyframe the IK targets planted during contact frames, bake, remove. For game work, export with the character stationary and let the engine drive movement.

A Realistic Quality Expectation

Single-camera capture gives you correct timing and readable poses, which is most of what makes motion feel alive and exactly the part that is slow to key by hand. Expect to spend your time on contact moments (feet, hands touching things) and on the few frames where the tracker guessed. That division of labor, machine blocks it in and you polish it, is the honest workflow, and it is still several times faster than keying from scratch.