So this may seem like an old, outdated question.... However, several years ago, I purchased the 3D Buzz Houdini Technical Effects DVD. It's been a while since I've had a chance to play around with Houdini. Recently in my professional life, I've moved from Lightwave and Softimage to Max. Having fun playing around with particles in Max using Box #3 has encouraged me to get back to playing around with Houdini. I've recently installed Houdini Apprentice 12 and while trying to go through the volume split tutorial, I encountered a problem.

In the initial setup, we lay down a geo operator and inside that, a popnet and a sphere with a copy. Within the popnet, we lay down a location, a force, a drag and a split. My problem arises when I get to the split operator. The activation for the split operator is set to $FF % 20 == 0.

As I step through the scene, I get the proper evaluations in the activation parameter but no the proper output in my scene. For instance, the expression evaluates to "1" at frame 20, however in the viewport, I do not see any additional particles added from the split pop. I do not see any split particles until frame 40. I would expect to see particles split at frames 20, 40, 60, ect... However, I only see additional particles split at frames 40, 100, 160, and 220... I'm having a hell of a time trying to figure out where this weird 20 frame offset comes from. I know I did this tutorial back n Houdini 9 and even if I had this problem back then, I don't recall any fix. I've searched the forum specifically for Houdini Tech Effects DVD problems but couldn't find anyting.

Any answers out there???