A number of artists I work with are interested in creating interactive work which includes the use of pre-recorded video sequences. While Houdini's CHOP's provide an excellent framework for managing interactive work and can control the 3D elements of Houdini in real time, there is no facility for triggering video sequences in real time (Houdini's compositor being ill suited to the task).

From this background was born Risch. Risch is a very primitive frame replayer which can connect to a Houdini pipeout chop via a socket, allowing the CHOP to act as a jog wheel for the image replay. Risch can be run on any number of computers, each connecting to a central copy of Houdini allowing any number of image sequences to be run without signifigant load on the control machine.

A frame sequence should be created and named in the form "basename.####.tiff" - the sequence MUST be padded to four digits, start at frame 1, and must be of type tiff with the file extension "tiff" (two f's!). Houdini should then be started, and a pipeout chop set up to export a single value using a socket (it will appear red until the connection is established). Risch can then be run by typing:

risch basename machineRunningHoudiniName 5000

where 5000 is the port number set up in the pipeout chop. Risch will default to using port 5000, as does Houdini, though this should be changed if multiple sequnces are being controlled.

Risch basically runs flat out displaying the frame number sent to it, as quickly as it can. However the code is not particularly optimised (It could be dramatically sped up if required), and can only handle 5-10 frames per second. The frame rate is controlled by the sampling rate of the CHOP - this should be set very low (say 1fps) initially and increased gradually to find the optimum rate.

It's questionable if the current frame rate is adequate for final deployment, but it is sufficient to prove the concept. I may be responsive to plee's to improve performance. In the mean time try reducing the resolution of your display to get a bigger picture from less data. You may use Risch freely provided suitable acknoledgement is given, and you inform me how it's being used.

Download Risch for IRIX
Download Risch for FreeBSD

Ian Stephenson.
DCT Systems
NCCA, Bournemouth University