Hey guys,

I have a HDA that I made for Maya with a built in output ROP. Its a particle emitter and it works fine when I key the emission on and off in the Maya view port but when I save to disc it ignores the keyframes and keeps going. To be more specific if I am on a frame with no particles it writes out blank files and when I am on a frame with particles when hitting the cache button it writes out the sequence of emitting points but does not stop.

I get the same problem with a bgeo rop and an alembic rop. It seems like a Sync Asset problem to me.

I am using houdini 15.5 and Maya 2016 extention 2 SP5.

Thanks
Zybrand

This is happening because when the output ROP is running, the Maya frame is not actually changing. When the output ROP is running, the Houdini world only gets a single frame snapshot of the Maya world. So from Houdini's point of view, it looks like the emission is not actually changing.

It's possible to workaround this with a bit of work. Instead of letting output ROP run for the entire frame range, the idea is to do one frame at a time. You'd need a script on the Maya side that steps through the Maya frame one at a time. And on each Maya frame, run the ROP for that one frame. This way, the Maya state would be reflected inside Houdini for each frame.

Hi Andrew, thanks for the explanation that makes sense. The solution is a bit overkill for what I am using to for so I'll just keep that asset in Houdini for now.