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View Full Version : Backface culling doesn't work when loading raw .obj files



TheSnidr
01-29-2014, 03:20 PM
I can export a raw .obj file of the track model in the editor of my 3D racing game. This only saves the vertex coordinates, UV coords and triangles. When imported into Lightwave Modeler, it looks like this:
http://imagizer.imageshack.us/v2/800x600q90/11/u17b.png
The geomtry is "shinier" than normal models created in lightwave, and backface culling doesn't work (if I flip triangles they're still visible). Why does this happen, and how do I turn settings back to normal modeler mode? For reference, here's what a normal model looks like for me:
http://imagizer.imageshack.us/v2/800x600q90/13/yzpf.png

JoePoe
01-29-2014, 06:53 PM
Is double sided turned on in Surface editor?
Sometimes Obj's come in with a Vertex Normal Map on. Set to none.... also in surface editor.
Have you tried Merge TrigonX (https://www.lightwave3d.com/assets/plugins/entry/mergetrigonsx/) to reconstitute back into quads? Not perfect but could get you pretty far.
And lastly, the shiny (if not fixed by the above) could just be a high spec value.

TheSnidr
01-30-2014, 02:13 AM
Ooh, thank you! Looks like the surface editor had all the options to get back to normal. I'm still puzzled why it happened in the first place though, but at least I can manually turn on backface culling and get the "correct" color:
http://imagizer.imageshack.us/v2/800x600q90/845/qjl1.png

JoePoe
01-30-2014, 05:35 PM
Ah, good! You're back on track...... :ohmy:

But something still looks off to me. Try "m" for merge and also unify polys (there might be duplicate geometry)... see what happens.
You can also turn on smoothing in Surface editor. Hopefully that will get rid of the track face/back faceting.
You could see what it looks like SubD (that'll smooth out your outer edges), but I'd prefer you to be in all quad for that (especially because you would need a couple control loops), and I think I still see tris.

Not sure what's going on where my arrow points to though, but try the above.

If you want, post the track lwo and I'll give it a look.

TheSnidr
02-02-2014, 08:44 AM
I only need to import the track into LW to build a level model around it. After the level model is done I can delete the track itself, import the model into the level editor and save the level!
But here you go, the raw .obj dump:
https://dl.dropboxusercontent.com/u/41252865/Cave.obj

JoePoe
02-02-2014, 09:42 AM
I only need to import the track into LW to build a level model around it. After the level model is done I can delete the track itself, import the model into the level editor and save the level!
But here you go, the raw .obj dump:
https://dl.dropboxusercontent.com/u/41252865/Cave.obj

Ah, okay, cool.
Just for future reference then.... merge got rid of over 7000 points. :)

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