I have a rather unusual question, we are using Metahumans and have access to mocap data from Vicon and Xsens. I’m curious if there are any tips, best practices to make Mocap retarget to Metahuman skeletons without solid issues. Particularly for optical data from systems like Vicon, but welcome to hear about Xsens tips as well.
With Retargeting in UE I can get two types of result - either off-balance or a great overall posture but with a solid amount of foot sliding. For context I also have experience of mocap retargeting outside of Unreal and with latest updates in IK Rig, I do get better results in UE than in MoBu.
I would rather not change metahuman bindpose for various reasons, so I will not mention that as an option. I’m choosing carefully which way to commit for, because it is a matter of large quantity of mocap data.
I’m curious if other teams / mocap facilities providers would deal this best if they resolve the optical marker data to metahuman skeletons.
I am aware of this method to use Speed Planting to fix foot sliding, I am not aware if it is widely used across other teams for animations from Optical Mocap data / I would imagine it more commonly with Xsens data /
More or less, I am interested if there is any feedback from other game dev teams dealing with high quality mocap data and metahumans. Any tips or knowhow are welcome.
Here are some some guidelines which we find eliminates foot sliding and provides good posture:
In the IK asset use a Full Body IK solver, set the Sub Iterations to 10, the Root Behaviour to Free, and the Global Pull Chain to 0.0.
Add settings to the hip bone, then set the Rotation Stiffness to 1.0.
For the leg chains, only set them to go as far as the Ankle, as supposed to the ball joint of the foot. Set the Chain Depth to 2.0 *Based on a hip/knee/ankle leg
In the Retarget Asset, set the Pelvis Motion operation’s Blend to source translation to 1.0, but then set the Z component of the weights to 0.0
On the Blend to Source sub operations of the Run IK Rig operation, set the Blend to Source of both leg chains to 1.0
Repeat the IK setup on both the performer and the target character.
In order to adjust the posture, we recommend setting up a performer and character in a level, whilst you tweak the edited retarget pose. This allows you to visualise the retarget in real time. We also recommend using Livelink hub recordings to playback ROM mocap data recorded from prior mocap sessions. This allows you to test ROMS in motion to tweak the retarget and also pause the recording to solve any tricky unique poses.
Here are some screenshots to support the guidelines above: