I have a human bipedal animation file format that I would like to programmatically read into Maya using the C++ API.
The animation file format is similar to that of the Open Asset Importer's per-node animation structure.
For every joint, there is a series of up to 60 3D vector keys (to describe the translation of the joint) and 60 quaternion keys (to describe the rotation of the joint). Every joint is guaranteed to have the same number of keys (or no keys at all).
The length (time in seconds) of the animation can be specified or changed (so that you can set the 60 keys to happen over 2 seconds for a 30 FPS animation, for example).
The translations and rotations of the joints propagates down the skeleton tree every frame, producing the animation.
Here's a sample. Additional remarks about the data structure are added by the logging facility. I have truncated the keys for brevity.
Bone Bip01
Parent null
60 Position Keys
0 0.000000 4.903561 99.240829 -0.000000
1 0.033333 4.541568 99.346550 -2.809127
2 0.066667 4.182590 99.490318 -5.616183
... (truncated)
57 1.366667 5.049816 99.042770 -116.122604
58 1.400000 4.902135 99.241692 -118.754120
59 1.400000 4.902135 99.241692 -118.754120
60 Rotation Keys
0 0.000000 -0.045869 0.777062 0.063631 0.624470
1 0.033333 -0.043855 0.775018 0.061495 0.627400
2 0.066667 -0.038545 0.769311 0.055818 0.635212
... (truncated)
57 1.366667 -0.048372 0.777612 0.065493 0.623402
58 1.400000 -0.045869 0.777062 0.063631 0.624470
59 1.400000 -0.045869 0.777062 0.063631 0.624470
Bone Bip01_Spine
Parent Bip01
60 Position Keys
...
60 Rotation Keys
...
In C++, the data structure I currently have corresponds to this:
std::unordered_map<string, std::vector<Vector3>> TranslationKeyTrack is used to map a set of translation vectors to the corresponding bone.
std::unordered_map<string, std::vector<Quaternion>> RotationKeyTrack is used to map a set of rotation quaternions to the corresponding bone.
Additional notes: There are some bones that do not move relative to its parent bone; these bones have no keys at all (but has an entry with 0 keys). There are also some bones that have only rotation, or only position keys. The skeleton data is stored in a separate file that I can already read into Maya using MFnIkJoint.
The bones specified in the animation file is 1:1 to the bones in that skeleton data.
Now I would like to import this animation data into Maya. However, I do not understand Maya's way of accepting animation data through its C++ API.
In particular, the MFnAnimCurve function set addKeyFrame or addKey accepts only a single floating point value tied to a time key, while I have a list of vectors and quaternions. MFnAnimCurve also accepts 'tangents'; after reading the documentation, I am still unsure of how to convert the data I have into these tangents.
My question is: How do I convert the data I have into something Maya understands?
I understand better with examples, so some sample code will be helpful.