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View Full Version : Why is .OBJ NOT the SAME .OBJ in all the applications



OOZZEE
01-25-2008, 09:57 AM
ok, I'm a little annoyed by this... I understand that every application has there own way of doing things behind the scenes... but why is it that an object exported or imported in the OBJ WaveFront format often gets distorted between applications ? Did WaveFront say to each software vendor "You each can tweak your own OBJ's to your personal agenda to mess up the work done by your competitors !"

I mean really, aren't those dev guys suppose to be the experts and understanding and creating a solid standard to exchange data accurately.

Seriously, open the same *.OBJ object in MODO, XSI, ZBRUSH, LW, & Others, and they all flip something, lose a poly, have a hole somewhere, or are completely screw up the original geometery ( especially with TEXT ) !! Not Always but MANY MANY TIMES !!

for a test to validate my sanity, I imported a simple sphere from LW9.3.1 to Zbrush3.1 ( and then SubD'd ) and it create really bad results.

Vendors should really try to put a little effort here ( sarcasm) :thumbsdow

beverins
01-25-2008, 10:31 AM
Well, I think the 3D market suffers from the attitude of "we know better" on the behalf of the engineers. A simple one is the World Axis, Is Z depth or is Y? Maybe X? This can have a knock on effect on how the .OBJ is encoded I think.

That's why there are attempts at a universal standard for 3d objects or conversions, like COLLADA, because the same issues you have with OBJ others have as well.

Plus, I think there is that personal agenda thing going - really! Luxology dropped support for the Lightwave Scene file, for example. No reason to. Their BusinessSpeak "reason" is complete nonsense. They did it purely to spite Newtek. Autodesk does the same thing. Why should they make it easy on the competitors and "waste their money". Their attitude is that if they make it harder for you to go between softwares, then you will decide to stay "in the family".

Fortunately, there are some softwares like Polytrans which try to fill that niche to satisfy the consumer and the artist.

Sil3
01-25-2008, 10:40 AM
Well... LW .obj exporter is a bit crappy to be polite so your trouble might start in there, or it could be something wrong on ZB side, like TRIS on a Spheres top that can become a mangled mesh...

But I know what you mean, a .TGA is a .TGA in ALL Aplications, so it is a .TIFF or a.JPEG... so why does every 3d tool decided to have its own Measure sistem and one object that is 1 meter can be 1Km or 1 mm or whatever it is like in XSi beats me...

Perhaps we are getting a to a consolidation point (about f****** time) or perhaps not... I hope we are, the days of "we are the best software out there" is long over time ago, we all use various tools.

calilifestyle
01-25-2008, 10:47 AM
im sorry but lux did not drop support.. remember lightwave change the way lwo files work. IF you pay attention to the modocast, one of them said that they where working on fixing the problem, at lest for the latest dot rev. but again i haven't read or heard that they have stopped trying to work out the problem. As for the obj format i have the same problem with iges coming out of solidworks. its all math right so it should convert but it doesnt.

StereoMike
01-25-2008, 12:06 PM
use polytrans granite pack for iges. works wonders. really.

I used moi before, but a friend with a mac spent me a copy of polytrans +granite + cad (he needed an iges conversion very urgent...) and...wow!

mike

Greenlaw
01-25-2008, 01:10 PM
Hi,

I was having a problem with LightWave's .obj format a while back, though I can't remember the specific issue right now--maybe some data was being lost between LW, Modo, and Headus UV Layout?

I used Accutrans to translate the data and it worked out great. It doesn't do everything Polytrans does, but it still does quite a lot, and it's pretty cheap too ($20). Go here:

http://www.micromouse.ca/index.html

Oops! That reminds me, I forgot to pay the license fee back then. Shame on me! I'm off to pay for it right now. :)

DRG

Lightwolf
01-25-2008, 01:15 PM
im sorry but lux did not drop support.. remember lightwave change the way lwo files work.
They completely dropped .lws support thoug... scene files.

...so it is a .TIFF...
Actually, TIFF is one of the most complex formats to read and there are only a few apps out there that can read all flavours.
In the CG world we tend to only use a sub-set of the possibilities here - and even then there's issues.

And Collada brings its onw set of problems. It is very specific - but that also requires a lot of flexibility by the reading application since it needs to cover all possibilities (not as much of an issue concerning geometry, but once animation comes into play....).

Cheers,
Mike

OOZZEE
01-25-2008, 02:10 PM
well, if we have to purchase third party apps to transfer files between apps, then what is the point in putting it in the original application in the first place ? They shoud just stick with their proprietary format and disregard the rest.

Most vendors advertise IMPORT AND EXPORT formats as a selling tool but yet cant get it right.

Lightwolf
01-25-2008, 02:57 PM
Most vendors advertise IMPORT AND EXPORT formats as a selling tool but yet cant get it right.
I suppose it shows how hard it is to do properly. There's more pipelines out there than applications (heck, everybody has his own pipeline) - and a developer can't check all of them.
If you have a reproducible issue, report it to the vendor, help them out. They are usually very, very grateful for user feedback (heck, I am, and I feel I get way to little).

Cheers,
Mike

Red_Oddity
01-25-2008, 03:00 PM
Most vendors advertise a lot, but when once in production the software becomes one big frustrating experience without a dedicated in house TD/R&D team (Maya comes to mind...daily...)

IMI
01-25-2008, 09:01 PM
OBJ is fairly straightforward, since it's really just a text file. Usually, the complaint with LW and OBJ is either the UV problem or the lack of .mtl support, or both.
The ZB problem is probably because LW's sphere creates both quads and triangles, by default. ZB prefers only one or the other. It's a good idea to make sure any meshes going into ZB have only quads, or only triangles.

In any event, unfair as it may seem, you do what you have to do, which is why it's a good idea to invest in a good 3D file format converter. Polytrans is an excellent converter, and very affordable. I tried it out, but didn't buy it since I've been using Deep Exploration for years, but Polytrans does do OBJ UV's cleaner, it seems.
It's not just LW, though. Probably all the 3D programs have their conversion problems, and if you do alot of shuffling back and forth between apps, it's a real good idea to have a good converter, just for those times when you encounter a problem

MooseDog
01-26-2008, 06:54 AM
afaik this applies to the .obj format: there's no one standard format, so writing and reading apps have to fudge and make decisions as to what to do. :lwicon: 's writing though is kludgy, but i don't know what they were looking at when the code was written.

IMI
01-26-2008, 07:16 AM
I don't have any overall problems with LW's OBJ import or export, except for the UV problem, which definitely is Newtek's doing. But aside from that, if you're going to use OBJ as an export, you have to do it correctly, Such as, no double-sided polygons, for one, and no overlapping UV's. Then again, I only use it for ZBrush these days, so my memory might be sketchy, but I used to use it alot more.
Aside from the lack of .mtl file support, Modeler has always imported OBJ files with no problems, at least in my experience.
Nowadays I just use .lwo for everything, and run it through Deep Exploration CAD Edition for any other formats I might want, for whatever reason.

GraphXs
01-26-2008, 08:34 PM
I use the OBJ export all the time in LW. I go to Z-Brush with quads and tri's in my mesh and Z-Brush loads the model fine. I do subd' the mesh at a higher level from LW so I don't have to subd' it alot in ZB. It does rotate the UV in ZB, but thats not a big issue. I also go to Max from LW using OBJ's and the only UV issue is that the verts aren't welded in UV space. Also for Objects that have overlaping geometry I export them as seperate pieces and load them into max so I don't get any flipped polys. Sure I wish I had a one click button that could do it all when going from softwae to software, but OBJ does work and keeps my meshes clean in other packages.:thumbsup:

Greenlaw
01-26-2008, 11:13 PM
I just remembered the problem I was having with LW's .obj. exporter.

Several months ago, I had wanted to bake a texture that was painted to a tiled UV map (probably from ZBrush,) to a new 'pelted' UV map that I created in Headus UV Layout. For some reason, if I exported the .obj from LightWave to UV Layout and back, the point order got messy and it became impossible to bake the texture to the second UV map. However, if the .obj was exported from Modo or Accutrans, to UV Layout, and then back to LightWave, it seemed to be fine. (Although I wound up doing the transfer baking through Modo anyway--it was just easier to deal with at the time.)

To be fair, this was quite a while back and I haven't tried it again with the latest release. If I have time, I'll test this with 9.3.1, although I don't believe the .obj exporter has been updated since.

That's all. Just thought it was worth mentioning since I brought it up earlier without any details.

DRG

Sil3
01-28-2008, 07:11 AM
I just remembered the problem I was having with LW's .obj. exporter.

Several months ago, I had wanted to bake a texture that was painted to a tiled UV map (probably from ZBrush,) to a new 'pelted' UV map that I created in Headus UV Layout. For some reason, if I exported the .obj from LightWave to UV Layout and back, the point order got messy and it became impossible to bake the texture to the second UV map. However, if the .obj was exported from Modo or Accutrans, to UV Layout, and then back to LightWave, it seemed to be fine. (Although I wound up doing the transfer baking through Modo anyway--it was just easier to deal with at the time.)



Im getting suspicious that Headus is messing with .OBJs point order... I never used it but today I read this on ZB Central:

http://www.zbrushcentral.com/zbc/showthread.php?t=55366&page=1&pp=15

I even liked this thread in there also.

Greenlaw
01-28-2008, 11:55 AM
Im getting suspicious that Headus is messing with .OBJs point order... I never used it but today I read this on ZB Central:

http://www.zbrushcentral.com/zbc/showthread.php?t=55366&page=1&pp=15

I even liked this thread in there also.

Actually, I've only had the point order issue when using LW's .obj export, and then bringing the .obj back again from another app. It works fine in LW if I use Modo, Accutrans, and Headus UV Layout's .obj exporter to move the file. In any case, this has only been a problem for me if I needed to bake a texture from a ZBrush tiled layout to a pelted layout created in another app (UV Layout or otherwise.)

DRG

IMI
01-28-2008, 12:05 PM
It seems I'm hearing more and more about Headus UV Layout these days. I had the demo, but never had the time to mess with it and now it's expired.
Is it all it seems to be cracked up to be?

Greenlaw
01-28-2008, 02:46 PM
It seems I'm hearing more and more about Headus UV Layout these days. I had the demo, but never had the time to mess with it and now it's expired.

Is it all it seems to be cracked up to be?

Hi,

It depends on your project situation and how much organic UV mapping you need to do.

UV Layout basically does just one thing, but it does it exceptionally well. The program can literally melt your mesh using physical dynamics to minimize stretching and compression. Like all professional tools, there's a learning curve involved, but once you've used it on a project you can pelt-unwrap just about anything in minutes. I use it for almost all the character and organic objects I work with these days. The 'melty' visual feedback happens in realtime so it can be fun to watch in action. I bought UV Layout to use on my own projects, but I've used my license on several projects here in the Box too.

In the past, I would have only recommended the program for organic objects, but recent versions have added alignment and straightening tools that make it suitable for 'hard' objects too. For example, I used to to unwrap a lot of armor and weapons, as well as the fleshy bits, in the last few game trailers we did.

UV Layout been a great program for me and some of my friends, but others in this forum have felt otherwise about it. Some critics complain about it's cost, and the application is clearly not intended for them. UV Layout may seem expensive, but it has saved me hours, if not days of tedious work everytime I use it, so in my situation it was well worth the purchase. If the time savings isn't worthwhile, there are less expensive and even free alternatives available.

And then some critics complain about its interface. To a degree I can understand this as the program is mostly operated through key commands and mouse movements, and there are no icons or buttons for most of these commands. This is the learning curve I mentioned. Fortunately, there are not a lot of commands to learn and if you apply it on a project, you can get used to it in a day or so.

By comparison, it's the most interactive UV program I've used, more so than even Modo which is also quite good. For UV mapping, UV layout is more fluid to work with and I feel I have more precise control, at least for organic objects.

My only complaint with the program is that you have to use .obj as a transfer format because UV Layout does not natively support .lwo. I understand that developer is willing to work with anyone who want to create a LightWave plug-in to hook into UV Layout, but I don't think there has been any takers yet. (Somebody has done this for Maya by the way.)

I'm not sure but I think you still can request a time limited demo. In any case, it's worth looking at the demo movies on the site if you're curious. Go here: http://www.uvlayout.com

DRG

Captain Obvious
01-28-2008, 04:36 PM
Plus, I think there is that personal agenda thing going - really! Luxology dropped support for the Lightwave Scene file, for example. No reason to. Their BusinessSpeak "reason" is complete nonsense. They did it purely to spite Newtek.
I'm not going to bother reading the whole thread, but this little piece of complete misinformation really annoys me. Do you want to know why Luxology dropped support for LWS? Because NewTek are rubbish at telling people when they change the format, and how they change it. LWS is a moving target, and I don't want Luxology wasting their time trying to keep up. It's better to let third parties solve it. A good friend of mine is working on a Python script for importing LWS files into modo, and it seems to work quite well. Luxology know pretty darned well that modo is a pipeline tool. It's not a full studio tool. You'd be hard pressed to find anyone who isn't a hobbyist using ONLY modo in their pipeline. Interoperability is key.

The idea that Luxology dropped LWS support to spite NewTek is completely preposterous.

IMI
01-28-2008, 06:41 PM
Thank you for the information, DRG, I think I am going to check it out. I do alot of UV mapping. Just about everything I model I UV map, even if I have no intention of needing a UV map for it.
I've been using a combination of Modeler, the "Nifty PLG" UV tools, and modo 203 for all this UV mapping. If Headus can replace all that shuffling around of files and do it better, I'm all for it. :)
I'll see if I can get my demo license extended, or see if there's a different version by now.

Greenlaw
01-29-2008, 01:18 PM
Hi,

I should have mentioned that 3D Brush now has UV mapping tools. The original release basically did just an atlas map, but the current version can split user specified seams and make a pelt map. I haven't tried this feature myself yet, but I think you can download a demo and try for yourself. FWIW, I have used 3D Brush for texture, normal, and displacement map painting and it works very well. The program is very inexpensive ($79), and it directly supports LightWave. (It even sets up normal map nodes in the Node Editor for you.)

For more info, go here:

http://www.3d-brush.com/

There's also good thread about it in this forum with participation by the developer:

http://www.newtek.com/forums/showthread.php?t=75262&highlight=brush

DRG

faulknermano
09-05-2008, 03:40 AM
Actually, I've only had the point order issue when using LW's .obj export, and then bringing the .obj back again from another app. It works fine in LW if I use Modo, Accutrans, and Headus UV Layout's .obj exporter to move the file. In any case, this has only been a problem for me if I needed to bake a texture from a ZBrush tiled layout to a pelted layout created in another app (UV Layout or otherwise.)

DRG


to others who might still be interested: i was getting the same problems with LW9.5, and decided, as a last resort to use the LW9.3.1's conv3d.p. and it worked as expected.

so my workflow was basically, export to ZB, sculpt, bring it back to LW for UV creation (for displacements), then bring back to ZB and replace ZBTool. no exploding mesh, so as long as i used 9.3.1.

i also noticed that LW9.5's conv3d.p no longer has the Export OBJ... i wonder where it is? inbuilt? at any rate, the new Export OBJ is a bit whacked out in respect to ZB at least.

STEEL TOE MEDIA
09-09-2008, 02:34 AM
Uh,i am currently involved in a project that uses 3ds, xsi, and maya. i use lw. when they send me stuff in the obj format, it is invariably garbage. requires a complete rebuild....when i send them stuff same thing. stupid. and i love lw. they have no prob sending stuff back and forth between themselves. its a lw issue. and it is annoying.

mattc
09-09-2008, 02:53 AM
i also noticed that LW9.5's conv3d.p no longer has the Export OBJ... i wonder where it is? inbuilt? at any rate, the new Export OBJ is a bit whacked out in respect to ZB at least.

it's part of valkyrie.p

M.

ben martin
09-09-2008, 06:58 AM
Uh,i am currently involved in a project that uses 3ds, xsi, and maya. i use lw. when they send me stuff in the obj format, it is invariably garbage. requires a complete rebuild....when i send them stuff same thing. stupid. and i love lw. they have no prob sending stuff back and forth between themselves. its a lw issue. and it is annoying.

You can try to use Blender to convert between formats.
Blender read and write OBJ as well LWO.

Give it a try, it's free!

faulknermano
09-09-2008, 10:07 AM
Uh,i am currently involved in a project that uses 3ds, xsi, and maya. i use lw. when they send me stuff in the obj format, it is invariably garbage. requires a complete rebuild....when i send them stuff same thing. stupid. and i love lw. they have no prob sending stuff back and forth between themselves. its a lw issue. and it is annoying.

well, all i can say is from a LW and Maya perspective. though it takes some special things to get OBJ from LW to Maya, in regards to point order LW is doing nothing wrong. only talking about point order: Maya internally mangles the OBJ from its actual form. i've actually written by own OBJ exporter for LW in hopes that i can force Maya to reinterpret the OBJ. but no luck... in this case of point order it's also Maya's OBJ handling that is the problem.

(as a result i built an MA exporter instead which runs reliably)

faulknermano
09-09-2008, 10:10 AM
it's part of valkyrie.p

M.

i see. thanks. strange though, you dont see the Export OBJ item even in the lwext9.cfg file anymore. it's like "inbuilt". and adding the 931 conv3d.p to a LW95 install wont work. :(

at any rate, the best solution is a well-defined, well-thought out workflow. i'm figuring it out still, to make most of the limitations.

Ztreem
09-09-2008, 11:30 AM
With LW9.5 the .obj exporter/importer got some updates. In my tests it works flawless, with vertexnormals,UV's and .mtl files, but I mostly use CAD/CAID applications.