MotionBuilder’s actor, is a handy tool, but it does not have a sufficient accuracy and precision for professional use. Let me explain its proc and cons.
To retarget the animation I started with these issues and achieved some success. At the moment this technology is as internal software of the Sevastopol mocap studio and is used in transfering process for a character animation.
What is wrong with this actor:
– Incorrectly referred to the rotation of the wrist;
– Wrong is the center of rotation of the back and pelvis. The center is shifted to the back, but must be on a good location in the center;
– The shoulder is very often goes astray and must be reduced;
– You can not specify action space offsets the arms and legs and head separately. There is only for the pelvis, legs and chest space;
– Ignores the fact that the bones may have DOF, such as arm only rotates on the Z axis for example. (Depending on the orientation of the bones);
– There is no possibility to connect the action space props to the actor, although it would be rational to introduce some actor extension as was done for the character.
– There is no way to specify the first retarget pose for a character in the retarget process from an actor to match between FK movement of the actor and the movement of the character’s skeleton.
Also an actor acute question for determining the centers of rotation, they are set up by hand and you can not calibrate them using the ROM (range of motion) animation.
What’s so good:
– First of all ease of use;
– It is possible to handle feet sliding… hard tool in use;
– Action space, IK/FK.
I am building a special skeleton, which is recorded by actor’s animation. Then the character is fitting under the posture of the first frame of an actor to ask the most obvious match for FK skeleton and using the script for porting an animation to transfer necessary parts of the body. I’ll show an example for hands.
The following picture shows the retarget of the animation using the standard actor:
The special skeleton is based on the center of rotation from the actor, however, for greater accuracy, it is desirable to calibrate by ROM animation and find the optimal center of rotations. This project SkeletonBuilder, I once mentioned is about it – http://neill3d.com/skeletonbuilder-wip