I've created a pyro sim in H14 and wrote the cache as a bgeo sequence. However reading it in H13 didn't work, i get the “unable to read” file error.

Am i the only one?

There are a couple of post-13.0 journal notes about file format changes: https://www.sidefx.com/index.php?option=com_journal&Itemid=213&page=index&journal=default&view=FULL&logfile=ALL&icon=ALL&version=ALL&buildstart=&buildend=&perpage=20&search=bgeo&find=Find [sidefx.com]

You could make sure you have at least 13.0.600, or setting the HOUDINI13_VOLUME_COMPATIBILITY env var. (The latter of course does not help with an existing sequence.)

Thanks Eetu, i've send a bug report to SESI, their answer:

"This was a bug that has been fixed in newer builds of Houdini. You can install a newer build of Houdini from our web site under Download -> Daily Builds. Please test 14.0.241

An alternative is to define the environment variable HOUDINI13_GEO_COMPATIBILITY in your H14 session.

Ahh, yes, they know better
There was indeed this journal entry [sidefx.com], if one knew what to search for..

The proposed solution from SESI didn't work (updating to version above 14.0.241), so i am currently setting the houdini env variable:

HOUDINI13_GEO_COMPATIBILITY = 1

@Eetu
do you know if there are big differences between the volumes?

Regards

IIRC, the big change is we moved the volume data to the end of the file to allow for shared volumes to not need separate data.

For example, if you use a Duplicate SOP to duplicate a 50MVoxel volume 10 times, Houdini will share the grids between those 10 copies. In Houdini 13, if you saved to disk, it would bloat back up 10x as each primitive would save its own data. In Houdini 14 we are able to instead share the saved data.

With VDBs, we switch on BLOSC compression of the vdb if that compatibility flag isn't set. (This is redundant if you are saving .bgeo.sc, but we keep it in case you have .bgeo as BLOSC is speedy enough we don't have to worry about re-compressing)

If you already have .bgeo sequences you need to move back, you can set the compatibility flag and run gconvert (in H14) to convert them from .bgeo->.bgeo. This will make them H13 compliant again.