To my knowledge OBJ supports one property of each type per mesh, but you should look up the OBJ specs to verify as I'm merely reciting from memory and never touch OBJ myself. I'm only familiar with the bugs that get reported to me which I must investigate.
In the case of softimage, the bug is the OBJ exporter does not make the distinction between Texture UVs, User Normals, and Vertex Colors when deciding what data to export. It looks for the first sample cluster property it can find and exports that. I think the error comes about because the OBJ exporter was written before User Normals truly existed and was probably coded on a false assumption about what would be available on a mesh for export. OBJ is a pretty simple format, even a novice scripter could write an OBJ importer/exporter if they wanted to. I haven't studied the OBJ files from Softimage vs. Max/Maya, so I don't know why the resulting file would be larger. Since OBJ is ASCII, probably a case Softimage being more verbose with descriptions. OK, official contest: Who can write the best OBJ importer and exporter toolset. Deadline: August 1, 2012 Winner gets a piece of Softimage swag from my 20 year archive. You must come to my annual Siggraph dinner to claim the prize ;-) And........GO! Matt From: [email protected] [mailto:[email protected]] On Behalf Of Williams, Wayne Sent: Thursday, April 26, 2012 12:01 PM To: [email protected] Subject: RE: OBJ exporter Yeah, I remember this convo from a ways back. Reordering things in the explorer view to get them to export properly was the solution you and szabolcs had mentioned. So you say obj only supports one of each type of sample cluster property per mesh. Does this mean that it supports only one property per mesh being exported.....or it supports one of each "type".....i.e. You can export user normals and one uv set...........but you wouldn't be able to get two uv sets out with a user normal as well? I'm guessing you mean the latter as it appears to be the case with max/maya obj export when getting smoothing groups/normals into game engines with UV's intact. Also, what was it again that makes the .obj files so much larger when exported from Soft? The way they handle UV's is inherently different which adds to the amount of data?? From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Matt Lind Sent: Thursday, April 26, 2012 2:13 PM To: [email protected]<mailto:[email protected]> Subject: RE: OBJ exporter BTW - I reported the bug long ago. From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Matt Lind Sent: Thursday, April 26, 2012 11:12 AM To: [email protected]<mailto:[email protected]> Subject: RE: OBJ exporter There is a limitation of OBJ only supporting 1 of each type of sample cluster property per mesh. But in the case of the Softimage OBJ exporter, I'd call it a design flaw as the user should be able to specify which of the existing sample cluster properties should go out the door. For example, an object with 2 texture projections. Matt From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Williams, Wayne Sent: Thursday, April 26, 2012 11:10 AM To: [email protected]<mailto:[email protected]> Subject: RE: OBJ exporter Is that an inherent limitation to the obj format itself? User normals and uv's appear to come out of max/maya properly no? From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Matt Lind Sent: Thursday, April 26, 2012 1:33 PM To: [email protected]<mailto:[email protected]> Subject: RE: OBJ exporter The issue with the OBJ exporter is it only exports a single sample cluster property. A sample cluster property is any of type: Texture UVs, User Normal, or Vertex Color. In our experience the OBJ exporter chooses and exports only the most recently created sample cluster on the object. Matt From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Szabolcs Matefy Sent: Thursday, April 26, 2012 12:24 AM To: [email protected]<mailto:[email protected]> Subject: OBJ exporter Hey guys, Can somebody (Stephen ;) ) confirm that the OBJ exporter is still broken? My issues so far: - UVs are not optimized (not welded) - If there is a user normal cluster UV data is not exported Cheers Szabolcs ___ This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission. If verification is required please request a hard-copy version. Crytek GmbH - http://www.crytek.com - Grüneburgweg 16-18, 60322 Frankfurt - HRB77322 Amtsgericht Frankfurt a. Main- UST IdentNr.: DE20432461 - Geschaeftsfuehrer: Avni Yerli, Cevat Yerli, Faruk Yerli
