Hey All,

What's the best practice for animating visibility in LOPs? I'm running into issues with keyframes on the enable checkbox on prune operators (when sent to render sometimes the objects in question appear, sometimes they just stay hidden).
I also tried animating a switch with a null, but ran into the same issue.

Many thanks,

Jules

I should probably add, this in Karma XPU.

It's a very simple animated prune. As I step through the nodes, flicking between on and off everything works fine until I hit the motion blur node (connected just before the Karma render settings). This seems to ignore the switch / not write time samples(?). anyone else encountered this?

Thanks,

Jules

You should animate the "Prune" parameter rather than the "Enable" checkbox. This ensures that the LOP always has an opinion about the visibility of the specified primitives, and you're just animating whether the prims should be visible or invisible. If the enable checkbox is animated, the Prune will only ever author "invisible" opinions, but it will author them at only certain times. These sound similar, but have very different results on the final stage. If you RMB on the Cache LOP and choose LOP Actions -> Inspect Active Layer, with an animated "Enable" checkbox, all the visibility opinions say "invisible" (though they are only authored at a few time samples). Compare this to the result of animating the Prune parameter (which was put there specifically so it can be animated this way), and you'll see a mix of "inherit" and "invisible" values on the visibility attributes. This will give you the animated visibility you want.

Also, make sure you are setting the "visibility" of the prims, not the "activation". USD doesn't support animated activation.

Awesome, Thank you!