C++ plugin for Foundry's Nuke software that calculates the motion vectors from a source frame to the current frame using a position reference pass or similar. It uses the nanoflann kd-tree library under the hood to do a nearest neighbour lookup using the xyz value of the supplied pref channel.
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| example image a smiley face drawn at frame 1 and warped to 5, 10 and 15 using a position reference pass |
Set the NUKE_VERSION CMake variable to the version of Nuke you wish to compile against, eg. 11.3v6 (tested version), assuming standard installation. Then it's just standard cmake build and make install commands for generation of the Nuke plugin.
- cmake /path/to/PRefToMotion/ -DNUKE_VERSION=11.3v6 -DCMAKE_INSTALL_PREFIX=~/.nuke -DCMAKE_BUILD_TYPE=DEBUG
- make install
PRefToMotion(.dylib|.so) should now be built and installed into your user's .nuke folder, so now it's just a matter of launching nuke and opening the test script pref_motion_example.nk
very simple list of parameters to interact with so far, the are:
- pref channels: channels that hold the xyz pref of similar data, if a 4th channel is supplied it will be used as a mask.
- uv channels: channels to store the uv data that is being generated
- source frame: source frame to calculate the motion vectors from.
- samples: number of nearest neighbours to look up, used to calculate a weighted average from the squared distance to the lookup point.
- modes: generates the motion as either an st map (normalised), uv map (vectors) or as the source pixels.
building the indices and querying a kd-tree with more than a million points can tend to be slow, optimisations forth coming.
example timing of building of a kd-tree with 1,063,379
--------------- kd tree ---------------
bbox: 91, 48, 1469, 1023
output channels: rgba,forward.u,forward.v
pref channels: rgb
num points: 1063379
samples: 3
source frame: 1
current frame: 15
--------------- timing ---------------
query time: 208 ms
build time: 1096 ms
total time: 1304 ms