I am trying to use OpenGL to render multiple simulations into one flipbook. (The way Scott Keating did in the 17.5 Launch, but I want to use OpenGL instead of Mantra, to render flipbook quality preview.)

I was able to use OpenGL with ROPfetch, which was faster than Mantra, by a few minutes, but much slower than OpenGL by itself (few seconds vs few minutes).

When using ROPfetch All Frames in One Batch enabled, it is as fast as OpenGL by itself, but cannot partition to create a vid

hip file is attached.

Any help anyone can offer would be appreciated!

Which build of Houdini are you using? In the latest build of 17.5, the partition by frame appears to be working as expected. In both the first and second branch of the graph it creates 100 partitions, each containing two work items.

The third branch won't work because there's no frame number on the work items in the file pattern node. You use an Attribute from String node to extract the frame number form the file name for each work item. Set the Source String to `@pdg_input` and the Pattern to {pdg_frame}.png.

sorry, build 17.5.293, and then 17.5.327, Indie license. Tried it on two computers and does not work, tried it on a third computer with Apprentice license, 17.5.327, does not work.

The ROPfetch at All Frames in One Batch renders the images fine, but all dots except for two are grayed out with state “Waiting. The Two that are green, state ”Cooking“.

The PartitionByFrame is stuck in perpetual state ”Waiting".

I had some errors when loading the .hip about missing assets, so I didn't try to cook it - I only generated the graph to verify the partitioner was working.

The problem is that you're pointing the ROP Fetch nodes to ROP Networks instead of a specific ROP. When cooking a batch, PDG needs to be alerted when each frame in the batch completes. It does that by hooking into the target ROP's pre/post frame callbacks, which the ROP Network itself doesn't have. If you change your ropfetch to point directly to the GL rop it should work as you expect.

wow, pointing it to the OpenGL ROP as you suggested works and partitions fine now. For some reason I was getting errors before, (can't remember exactly–something about cannot find opengl rop)

In any case, thank you for helping! I believe the problem is solved. For anyone interested, the attached file generates flipbook quality previews for sims (just point the ROPfetch to the opengl rop).