VDB loop glitch

rileycoyote · June 28, 2020, 7:29pm

Cross posting this from several other forums. Using C4D R21, latest Redshift, latest TFD.

Been exporting looping vdbs from houdini. They work well but I’m noticing something weird. If I go into negative frames on the C4D timeline (ie. playback head at frame -1 and beyond) some of the vdb’s channels disappear and therefore do not render. It’s strange because it only does it on some of them. I use the same houdini patch for all of them. Which is just a timeshift and blendshapes to create the loop. The vdbs are created in TFD. See attached gif of frame 0 vs frame -1.

Jascha_Wetzel · June 29, 2020, 9:39am

A couple of tests/questions come to mind:

Are the frame numbers the same in Houdini, that is also negative frames?
And are the problematic frames and channels displayed in Houdini correctly?
Do the negative frame numbers show up in the filenames correctly?
If you load the individual files from a problematic frame into C4D, are the channels missing as well? If so, how about if you load the same individual file into Houdini?

Paul_Selhi · June 29, 2020, 7:22pm

The VDB’s are created in TFD ? Excuse my ignorance but where does Houdini come into this ?

rileycoyote · June 29, 2020, 7:34pm

I take the cache of TFD sim, convert to vdb, import into houdini looping patch, export, import into redshift volume object with looping animation settings. My hunch is a redshift volume object / c4d error. But I am all ears.

rileycoyote · June 30, 2020, 7:26am

I solved it. The VDBs that were working all had some kind of positive start frame offset. I changed the problematic ones to all have some variation of a start frame offset and now they all are cool beans.

Jascha_Wetzel · June 30, 2020, 7:31am

Is this the frame offset in Houdini, TFD or Redshift?

rileycoyote · June 30, 2020, 7:31am

Redshift volume object animation settings. For whatever reason going into negative frames on the timeline caused the channel to disappear. Was important for me to be able to go into negative frames based on how I’m setting up my animation. As long as there is at least 1+ start frame offset they work. And the offset needs to be as many negative frames as going back. So if timeline playback head is at -5 and the offset is only 4, it will again disappear.

You can mark resolved.