With mo-cap on the rise as a technology to get great, realistic animation fast it’s good to have a handle on it. Film and especially games are moving more and more into this technology and it’s easy to see why, it’s quick and requires a lot less man hours to create. Problem is, as intelligent as computers are they just can’t replicate the human addition that an animator adds. We add life and a soul into the character something that I think a computer can never reproduce.
Even though mo-cap does make the animation process much more efficient, someone has to clean up this data we get from the mo-cap process. First off if you haven’t worked with mo-cap you will not realize that it keys ‘ever single frame’ this is where as a cleanup artist or animator we do most of our work with this. We have to sometimes clean up all the unnecessary keys and remove anything that is moving out of the ordinary. The following tips I have are for getting into some particularly bad mo-cap and how to clean it up.
Before I move on though I must note that sometimes the mo-cap is just too messy to work with and at that point I opt to hand key using the mo-cap as a guide for the body mechanics.
The Euler Filter (It will become your best friend and fighter against Gimbal)
My first tip is when you get the mo-cap into the scene, the first thing I will do is run a Euler filter tool on all the curves in the Graph Editor. (In Maya this is under Curves –>Euler Filter) This will remove anything that is, for lack of a better word, flipping and remove gimbal. This will make it so when you do start removing any unnecessary keys you won’t suddenly have a character rolling around all over the place.
These are what bad curves look like... not pretty!
The main idea with mo-cap is to get the general flow the curves and remove any sudden jitters in the curves. I suggest starting at the COG or hips and working your way up to the chest bone. From her you can then do either the head and neck and the arms. Work down the chain because if you find the sudden jerking movement in the hips that could show up in the arms and rather than try to find the problem in the arms, you will realize that its the hips that are driving that jerking movement in the arms.
Create a buffer curve snapshot to see where you're curves were.
At this point I would also suggest turning on the Buffer Curve Snapshot tool (if you’re using Maya see above), then turn on Show Buffer Curves (under View –> Show Buffer Curves). This way you can see where the curves were and when you delete the messy keys you can at least follow the flow the original gave you.
Duplicate Special options.
My last tip is if the mo-cap is just unworkable there are a few ways you could tackle this. My first tip is duplicate the original rig model and all using Duplicate Special, make sure you select the options box. In the options for this make sure Duplicate Imput Graph is ticked, then hit Duplicate Special. This way you now that a duplicate rig you can trace. Create a layer add this rig and make it a template. Now import or zero out all the controls on the original one and start tracing. I only suggest this way if the curves are just a complete mess.
There is a slightly different way of doing this though without having to hand key from scratch. Go through the animation and find the ‘key’ frames and main breakdowns, then delete everything between these keys. This method is basically working like a traditional animator would, you would find the key frames that will give you the most information about the movement in the mo-cap.
Pretty curves... now don't they just look nice.
I hope this helps someone who is getting into animation or even someone going into a new job involving mo-cap wrangling. It really is an art form in itself and something that I am constantly learning new tricks on handling. Next time I will post some tips on getting a good cycle from mo-cap without changing any of the vital curves. Happy animating!
