Maya AnimCurve Match

Matches a sparse Maya animCurve to a dense animCurve using a Non-linear Least Squares algorithm.

This plug-in command can be used to help create simplified animCurves using less keyframes, while matching closely to the original densely baked animation curve.

Uses of this plug-in are:

• animCurve sub-division (increasing keyframes)
• animCurve keyframe reduction (used to match to a reference curve)
• Motion Capture animCurve clean-up and re-targeting.
• Animated space switching, while keeping world space positioning (re-parenting a child node into world, while keeping the original keyframe positions, and re-adjusting tangents).

Features

• Calculates animCurve keyframe values, tangents and times to fit a different animCurve (dense or sparse).
• Ability to adjusting:
  • Keyframe Value
  • Keyframe Time
  • Keyframe Tangents
• Creation of new animCurve curve, with given name.
• When start/end keyframe times do not match source curve, scaling the destination curve to the correct start/end times is possible.
• Maya Undo / Redo support.

Usage

Here is a simple example of how to use the animCurveMatch command.

start = 1
end = 10

import math
import maya.cmds

# Load Plugin
maya.cmds.loadPlugin('animCurveMatch')

tfm, shp = maya.cmds.polySphere()

maya.cmds.setKeyframe(tfm, attribute='translateX', time=start, value=10)
maya.cmds.setKeyframe(tfm, attribute='translateX', time=end, value=-10)

for i in range(start, end+1):
    v = math.cos((float(i-1) / float(end-1)) * math.pi)
    maya.cmds.setKeyframe(tfm, attribute='translateZ', time=i, value=v)
maya.cmds.keyTangent(tfm, inTangentType='spline', outTangentType='spline', time=())

srcCurve = maya.cmds.listConnections(tfm + '.translateZ', type='animCurve')[0]
dstCurve = maya.cmds.listConnections(tfm + '.translateX', type='animCurve')[0]

# Run command! This will modify 'dstCurve' animCurve.
maya.cmds.animCurveMatch(srcCurve, dstCurve, iterations=1000)

See 'test.py' for more details

Command Flags

The command syntax is:

animCurveMatch <source> <destination> [flags]

The command can be run in both MEL and Python.

MEL:

animCurveMatch "srcCurve" "dstCurve" -iterations 1000;

Python:

maya.cmds.animCurveMatch("srcCurve", "dstCurve", iterations=1000)

Here is a table of command flags, as currently specified in the command. Note some are "UNSUPPORTED", these flags have been added, but do not function correctly.

Flag	Type	Description	Default Value
-name (-n)	string	The name for the new animCurve created, must be a unique name.	name_solved
-iterations (-it)	int	Number of iterations to perform.	1000
-adjustValues (-avl)	bool	Adjust the keyframe values to minimise differences.	true
-adjustTimes (-atm)	bool	Adjust the keyframe times to minimise differences.	false
-adjustTangentAngles (-ata)	bool	Adjust the keyframe tangent angles to minimise differences.	true
-adjustTangentWeights (-atw)	bool	UNSUPPORTED - Adjust the keyframe tangent angles to minimise differences.	false
-forceWholeFrames (-fwf)	bool	When adjusting keyframe times, only modify time values by +/- 1.0.	true
-scaleTimeKeys (-stk)	bool	Re-maps destination animCurves keyframe times to start/end of source animCurve.	true
-addKeys (-ak)	bool	UNSUPPORTED - Allow adding keyframes to reduce the error.	false
-newCurve (-nw)	bool	If true, the destination animCurve is copied and renamed, otherwise the destination animCurve is modified in-place.	false

Building and Install

Dependencies

• C++ compiler with support for C++11
• CMake 2.6+
• levmar 2.6+ (http://users.ics.forth.gr/~lourakis/levmar/)
• Autodesk Maya 2016+

Build and Install

Run the following in a Bash-like shell:

Build Levmar

Building Levmar is quite simple. Levmar does not have an 'make install', and it will only compile a static library, which we will link against in the next step.

$ tar -xf levmar-2.6.tgz
$ cd levmar-2.6
$ mkdir build
$ cd build
$ cmake -DNEED_F2C=0 -DHAVE_LAPACK=0 -DBUILD_DEMO=0 ..
-- The C compiler identification is GNU 4.4.7
-- The CXX compiler identification is GNU 4.4.7
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/example/directory/levmar-2.6/build
$ make
Scanning dependencies of target levmar
[ 14%] Building C object CMakeFiles/levmar.dir/lm.c.o
[ 28%] Building C object CMakeFiles/levmar.dir/Axb.c.o
[ 42%] Building C object CMakeFiles/levmar.dir/misc.c.o
In file included from /home/davidc/bin/levmar/test/levmar-2.6/misc.c:47:
/path/to/example/directory/levmar-2.6/misc_core.c:577:2: warning: #warning LAPACK not available, LU will be used for matrix inversion when computing the covariance; this might be unstable at times
In file included from /path/to/example/directory/levmar-2.6/misc.c:64:
/path/to/example/directory/levmar-2.6/misc_core.c:577:2: warning: #warning LAPACK not available, LU will be used for matrix inversion when computing the covariance; this might be unstable at times
[ 57%] Building C object CMakeFiles/levmar.dir/lmlec.c.o
/path/to/example/directory/levmar-2.6/lmlec.c:39:2: warning: #warning Linearly constrained optimization requires LAPACK and was not compiled!
[ 71%] Building C object CMakeFiles/levmar.dir/lmbc.c.o
[ 85%] Building C object CMakeFiles/levmar.dir/lmblec.c.o
/path/to/example/directory/levmar-2.6/lmblec.c:39:2: warning: #warning Combined box and linearly constrained optimization requires LAPACK and was not compiled!
[100%] Building C object CMakeFiles/levmar.dir/lmbleic.c.o
/path/to/example/directory/levmar-2.6/lmbleic.c:40:2: warning: #warning Linear inequalities constrained optimization requires LAPACK and was not compiled!
Linking C static library liblevmar.a
[100%] Built target levmar
$ ls -l -h liblevmar.a
-rw-rw-r--. 1 user user 97K Aug 22 13:19 liblevmar.a

Note we do not use the LAPACK library, we do not need it. If you would like to compile with LAPACK, you'll need to change your cmake flags accordingly.

Build animCurveMatch

To compile the Maya plugin, run the commands.

$ cd <project root>
$ mkdir build
$ cd build
$ cmake \
  -DMAYA_INCLUDE_PATH=/path/to/maya/include \
  -DMAYA_LIB_PATH=/path/to/maya/lib \
  -DLEVMAR_LIB_PATH=/path/to/levmar/lib
  -DLEVMAR_INCLUDE_PATH=/path/to/levmar/include ..
$ make -j 4

Install animCurveMatch

Now lets install into our home directory maya 'plug-ins' directory.

$ mkdir ~/maya/<maya version>/plug-ins
$ cp animCurveMatch.so ~/maya/<maya version>/plug-ins

Limitations and Known Bugs

• Adjusting Tangent Weights does not currently work.
• Adding or removing keyframes is not supported.