Isotropix Forums

Is there a way to import OBJs with groups ie not flattened?
It would be great to not loose the model hierarchy upon import.

Hi,

No that's only possible in alembic, usd and lwo format.

Cheers

Are you thinking of adding that functionality for OBJ? It would be very handy...

No, we favor support for Alembic and more specifically USD. OBJ is an ancient format from the last century.

Ok ok... just very widely supported. Not sure why it's a big deal. Surprising that it doesn't work. All the other software loads the groups.

I probably explained this somewhere in the forums a long time ago. In a nutshell:
Unlike other packages, Clarisse references the original OBJ file. Creating multiple nodes based on the ascii OBJ file is very inefficient since to load each group independently, each node would have to load the entire file, and seek where the group starts. Since we don't want to load the file multiple times...

Yet again, Clarisse supports LWO files with layers. That one is not inefficient because it's very easy to seek and skip to the right layer without loading the entire file since the file format is in binary.

Thanks for the background. The issue is that there is several software inputs that do not generate the other formats (only OBJ) so need to somehow convert each file with another package and break apart the components into separate OBJ files or another format somehow. that gets quite time consuming with a lot of files or components.

Just food for thought: what if there was a way to break apart the OBJ into separate files upon import automatically? (import flat or import break-apart)? it would be fully ok if there is extra files locally.

If you want to do something here is a starting base:
viewtopic.php?f=21&t=5307&p=19071

Obviously the best would be to create a standalone C++ converter that would convert an OBJ to USD/Alembic. Not really that complicated to do if you know these libraries. Have you googled it? It probably exists.

You could use Blender I guess to import as OBJ and export as Alembic/USD.