I modeled an object in Modo and exported it as an .obj with material groups. When I bring it in to Houdini, the material groups don't show up. I don't know if it is just the materials from the .mtl file that aren't showing up or if the groups themselves aren't showing up either. How do I get the .obj to import with material groups or at least poly groups that I can assign materials to? I also checked the .obj in 3ds max and the material groups showed up there so it isn't a problem with the .obj file.

Thanks
Alex Gansert

You can check on the forum that Houdini will not import .mtl information linked to the .obj.
I don't understand that choice from Sidefx as many programs handle obj/mtl actually.
One solution is to use the autodesk fbx converter and import the fbx file into houdini.

one of my first tests when I migrated to Houdini was to get OBJ with MTL files (from XSI) into Houdini the more effortless as possible .. and here's my python script attempt at the time:
http://forums.odforce.net/index.php?showtopic=4029&hl=python+telnet [forums.odforce.net]

once opened a telnet port on Houdini and ran the script you could see houdini creating all the network, from SOP to SHOP.. and pointgroups and assigning the materials .. and all the needed attriutes like UV and such.

I personally didn't tested since then so I'm not sure it'll work on Houdini 11 either

also, please keep in mind that it was a personal joint effort to learn Python and Houdini at the same time .. so beside it did work for my needs at the time (I was on Houdini 8 ) it might not be the most elegant piece of code you'll find around, I would personally completly rewrite whole of it differently now .. and also I'm not sure it was working on any other exported OBJ than the one from XSI.
for some reason the OBJ _Mtl files differs when exported from different packages, at the time I needed to deal with XSI so I didn't go on implementing Maya's OBJ file reading.

hope that helps somehow.

cheers!

as said elsewhere on the forums…obj simply isn't used that much in professional production - it's not that obj is a bad format, just that there are others that are WAY better…and the mtl file only supports the most basic of surfacing propeties, again not suitible for professional work…
and even with these other, better formats, once I get something into Houdini I make it a bgeo as soon as I can…

thanks for the code sum][one