Deborah R. Fowler
Python
in Houdini Example - Mocap data parsing
Updated May 9 2013
Updated July 11 2018
Mocap data parsing - related to Exercise 3 for 705 is motion capture data parsing. Here are some simple examples of using the copy node (for example, a mace). You must create your own commented python script as the first part of this exercise.
NOTE: This is an exercise in scripting - you can bring in mocap data more easily by importing an fbx
This example is modified slightly from Nate Usiak's work in VSFX 705 in 2012 and inspired by Malcolm Kesson's site www.fundza.com.
To process data into a format suitable for Houdini a script written by Nate Usiak is given here.
This takes data from ascii txt format as found at http://accad.osu.edu/research/mocap/mocap_data.htm.
Thanks to the Motion Capture Lab of the Advanced Computing Center for the Arts and Design, Ohio State University.
This quarter, data from bvh format will be used.
Once that data is parsed ...
To take the resulting data into Houdini you must create a digital asset.
1. File->New Operator Type – brings up a dialogue box.
- name it appropriately ie. fields Operator Name and Label
- Operator Style must be set to Python Type
- Network Type must be set to Geometry Operator
- Save To Library should point to your local folder (don’t forget to hand in the otl!)
2. Hit Accept – an Edit Operator Type Properties window appears
In the Basic tab be sure to set Minimum Inputs and Maximum Inputs to zero.
set the Label to be something unique (maybe include your name)
In the Parameters tab set up two variables, one for the data files, one for velocity
(these parameters will be used in the code tab – they must match
I’ve used mocapFiles and velocityScale)
In the Code tab place the script (courtesy of Nate Usiak found here)
make sure your parameters for source_file and velocity_scale match the code
ie. what is in quotes should be the names you used above ie.
mocapFiles and velocityScale
3. Throw down a geo node
- bring in a “mocap” node (from your digital asset – hit tab and select the digital asset).
- Point the mocapFiles parameter to your files
- make sure velocityScale is set to 1 and you are all set.
See my powerpoint
for step by step screensnaps
A similar technique is used with python
parsing and into mel. The sample script is here (by Sorya Serei)