[Sidefx-houdini-list] Point Instancing Animation

Dan Seddon dan.seddon at framestore-cfc.com
Mon Aug 14 10:45:44 EDT 2006

> Yea, I was looking for some kind of per frame instance attribute but 
> couldn't find it. Seems like the "render from archive" feature only 
> works from Object level.
> The other problem with the method I sent to Jaideep is that it doesn't 
> take velocity into account. In many cases it might be desirable to 
> play the animation faster or slower based on the particle velocity. 
> While it's possible to set up inter-frame geometry blending at the SOP 
> level, I'm not sure how to pass the information from the POP up to the 
> referenced SOP.
Ahh.. I ran in to this as well, but it is solvable. Essentially you are 
instancing "objects" so the only m-blur that is appropriate is 
Transformation-Blur, it does do this, if you were to put $FF in to a 
transform sop you'd get the result you'd expect. The problem with 
particles is that they don't give you subframe positions so the shutter 
breaks and you might then want to cheat the velocity as you mentioned - 
the solution to which is to build them yourself by adding the velocity 
back on to the position multiplied by you're time offset i.e.
In a point Sop $TX would become:

$TX + $VX/$FPS*($FF-floor($FF))

and the same for $TY and $TZ.



More information about the Sidefx-houdini-list mailing list