render to texture problem

garriola83

hi, im using 3ds max 2008 to render to texture an AO material, but for some reason my renders always seem to be missing big pieces of my model. everything ive gotten is unwrapped correctly. could it be a map channel problem? im rendering my texture in map channel 3. if so, how can i make all my surfaces to map channel 3? thanks!

garriola83

heres my unwrap

and heres my AO

j_bradford

Make sure the pieces that are missing aren't flipped (IE. mirrored). MR has an issue with rendering flipped/mirrored UVs. Best way to check is make a check map with letters on it, 5x5 tiling and see if the letters are facing the wrong way.

Eric Chadwick

There's also a "Select Inverted" command in the Unwrap window.

j_bradford

Thanks for the heads up!

Joshua Stubbles

EricChadwick wrote: »

There's also a "Select Inverted" command in the Unwrap window.

That's a damn good tip I was oblivious to.
Thanks.

garriola83

oh wow thanks, geez didnt know that at all. THANKS SO MUCH!

garriola83

whoa actually that didnt work. i flipped the ones that are inverted and still wouldnt make a baked texxture

garriola83

oh after some tedious face flipping i finally got it! thanks everyone!

HarlequiN

Probably a bit late to aid that much, but here's some things to avoid which should minimise face flipping in future.

1) Never use Max's Mirror tool. Instead, use the Mirror or symetry modifiers in your stack - the mirror tool screws x-forms, resulting in mirrored faces you can't see on the mesh. If you then continue to model using Edit Poly you can end up with a combination of flipped and unflipped normals on the same mesh, which is a bugger to sort out.

2) Avoid scaling objects using the Scale tool. Instead, wherever possible, go into a sub-object mode of Edit Poly (I like vertex mode personally), select everything and then scale down using the scale tool. Again, scaling the object directly can screw your object's X-forms (though less likely to result in flipped faces, it i spossible if you scale to a minus amount by mistake).

3) If you do end up doing any of the above reset the X-Forms right away (It's under the Tools panel I think - Panel to the far right, icon looks like a hammer), and then, if the faces become flipped, select them all and flip them back - saves messing around later on.

You may have known all that, but X-Forms are a really irritating part of Max that a lot of people don't know about until they've had probems with them a few times.

garriola83

HarlequiN wrote: »

Probably a bit late to aid that much, but here's some things to avoid which should minimise face flipping in future.

1) Never use Max's Mirror tool. Instead, use the Mirror or symetry modifiers in your stack - the mirror tool screws x-forms, resulting in mirrored faces you can't see on the mesh. If you then continue to model using Edit Poly you can end up with a combination of flipped and unflipped normals on the same mesh, which is a bugger to sort out.

2) Avoid scaling objects using the Scale tool. Instead, wherever possible, go into a sub-object mode of Edit Poly (I like vertex mode personally), select everything and then scale down using the scale tool. Again, scaling the object directly can screw your object's X-forms (though less likely to result in flipped faces, it i spossible if you scale to a minus amount by mistake).

3) If you do end up doing any of the above reset the X-Forms right away (It's under the Tools panel I think - Panel to the far right, icon looks like a hammer), and then, if the faces become flipped, select them all and flip them back - saves messing around later on.

You may have known all that, but X-Forms are a really irritating part of Max that a lot of people don't know about until they've had probems with them a few times.

thanks for all the help. for some reason, some faces were "supposedly" flipped, and when i flipped them over, they would render black. i turned on backfaced cull and my model consisted of half flipped and half normals are facing right. i checked the uvws and selected flipped faces and none was selected. WHAT?! i know, right?! i just remodeled the whole thing. the whole ordeal was irritating, ive never had this happen before. thanks tho.

Eric Chadwick

The STL Check modifier is also another helpful tool, if you didn't know about it already. It selects problem faces or edges automatically, depending on the problem (doubled, flipped, open, etc.) so you can easily find what needs fixing.

HarlequiN

Good point Eric, I'd forgotten about that. The only thing to note there is that it switches you to edit mesh (or at least it does in the version I'm using. 9 I think). Not a big deal, but worth noting in case you need to be in edit poly and forget to switch back

Interesting trivia: STL is short for STereoLithography, and is actually a file format used in things like rapid prototyping. Despite it's intended purpose it comes in really handy for Game Art too.

Eric Chadwick

I find it bizarre sometimes how much the old tricks still get used. Maybe that's just how old of a dog Max is.