**Please note that due to the 2020 COVID Pandemic these were pre-captured mocap files.** Intro: The goal for this project/exercise is to pick at least 3 takes from previously recorded motion capture data, find a model/skeleton to work with retargeting problems and add expressiveness if appropriate. With these takes, it was also necessary to utilize character settings and a control-rig to plot and remap data onto a virtual character of our choosing. Because of the nature of the project, I used a simple "woman athlete" rig for the sake of understanding the technicalities of plotting, retargeting, and implementing more expressive motion. There's the additional task of fixing faulty data if needed. Editing within MotionBuilder: When initially bringing in a new take of animation, and a separate character model/skeleton, it is important to attempt to "zero" out the initial T-pose of the character in order to properly retarget your desired skeleton/model. It should be noted that you want to do this for BOTH the character model and the motion-capture skeleton, as forgoing one will ultimately leave undesired issues with retargeting in the long run. After retargeting, there becomes an artistic task of fidgeting with numbers that correspond to how the imported skeleton will stretch/reach to the animated one. There's the ability to adjust a myriad of settings--I like to recall the children's limerick, "head, shoulders, knees, and toes". Though in this case there is a proper order to making these work. I suggest beginning internally (stomach area) and move towards outer extremities (hands and feet). One should begin with adjusting the hips and attempting to solve match the root joint of the entire skeletal structure. The spine is the next task to take care of, as there is often over/under-extension making your character look like they're bent/slouching. I often found moving onto the shoulders helps with any of the issues with the arms and makes retargeting a breeze once you've found a realistic shoulder look. After this, move onto the knees and the position of the feet--you'll often find that your imported model will have spacing issues with their ankles, and this can easily be fixed. The intensity of the "reach" is from a 0-100 scale: 0 being the base configuration, 100 being a complete "stick" to the motion capture take. Be advised that using 100 will more than often result in "jumping" issues with the joints; as the skeleton can/not reach, it will appear to "click" into place many times. A safe bet is often to just go with 50, and move periodically up/down the scale for finer adjustments. Also, remember that if your character is very dynamic over a long period of time, you can "key" these values periodically depending on the motion. Outcomes:
Above you can find a video example of before and after the edited sequences. This exercise taught me how to work with control rigs, too, as this can provide extra animation layers that allow for nuanced movement. These layers can be stacked one on top of the other, and allow the animator to switch between them if there's a need. For example, if one wanted to edit only the wrist movement like a waving hand, and then edit the elbow animation, these can be separate layers. After making the changes, the animator is able to add even more motion without affecting the initial elbow/wrist movement. I found most of the time that I would first edit the motion with a smooth/butterworth filter to remove any unnecessary slips/glitches in the motion, then create a control rig with animation layers, and re-bake the animation back to the skeleton as needed. Comments are closed.
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May 2020
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