It looks like the UV's may of been stretched. Can you take a textured screen shot in max with just a checker board texture?

Ah ok, pic is here:



I did manually edit the tyre tread UV's as when I applied the checker texture the checks on the side of the tyre were wider than the ones across the width, even though they were part of the same UV. I therefore re-spaced that whole UV section to try and get the checkers to be more the same size around the tyre, maybe I messed it up somewhere along the way

Yeah, that doesn't look right, might want to consider to cut the tire up in two halves and place one of them +1 in the uv-space, giving it more room in the compressed direction (in this case the up/down part of the UV).
Should always aim towards getting as average checker size in both direction to be the just about the same, obviously its not completely possible because the inner and outer part will be different sizes, but try get some kind of compromise.

Alright cool I'll give that a go after work tomorrow and see how it goes, thanks

I would think about tiling the tread area, instead of using unique UVs for the whole circumference. This will give you a lot more resolution.

Might give that a shot then, probably need a bit of clarification on the process for doing that though...I'd *guess* it would involve unwrapping the whole tyre, separating out a section of the tread and moving the rest out of the UV area, then scaling the tread section up, baking the normals on to it, then taking the high detail tread section, scaling it down and re-combining it with the other UV's? Then copying it around the circumference?

Originally Posted by PHaynes888

Might give that a shot then, probably need a bit of clarification on the process for doing that though...I'd *guess* it would involve unwrapping the whole tyre, separating out a section of the tread and moving the rest out of the UV area, then scaling the tread section up, baking the normals on to it, then taking the high detail tread section, scaling it down and re-combining it with the other UV's? Then copying it around the circumference?

Well you wouldn't have to do that.

I'd suggest simply mirroring the tyre tread into quarters or halves. It does depend on what kind of specs you're working to. Chasing high texture resolution sometimes isn't worth it if it causes visible seams all over your model.

Ok, so i deleted half of the treads and am just unwrapping one half, so that, as you guys say I can get more definition and detail in. The normal map now looks like this:

http://img859.imageshack.us/img859/8...sxnormalno.jpg

Looking at the two main elements on it (left hand side and bottom right) I can see some artifacts on the inside of the tyre rim, not sure if the tyre tread looks good or bad though? You guys will have to tell me that...

I rendered out the low poly with the normal map applied. It seems that the treads may be inverted and in general the normal map is a bit wavy. I assume the wavyness is because I didn't straighten out my UV's before baking? Which I can do easily if need be. How would I go about properly flipping these inverted treads though?

http://img217.imageshack.us/img217/2391/tyrenormal.jpg

Cheers!

Invert the green chanel of the normalmap.

Originally Posted by PHaynes888

I rendered out the low poly with the normal map applied. It seems that the treads may be inverted and in general the normal map is a bit wavy. I assume the wavyness is because I didn't straighten out my UV's before baking? Which I can do easily if need be. How would I go about properly flipping these inverted treads though?

the wavyness is because you're projecting a cylinder onto a series of planes. It's not possible to get rid of it altogether.

There's a whole thread about it:
http://www.polycount.com/forum/showthread.php?t=81154

Ok, so following the advice of that thread above (cheers sprunghunt) I got rid of some of the wavyness, I think I may need to subdivide my low poly up a little more to get rid of some of the existing kinks. This is how it's looking currently:

http://img718.imageshack.us/img718/8...sxnormalno.jpg

http://img100.imageshack.us/img100/3751/treads.jpg

I have some more questions...

- There are obvious artifacts on the normal map and therefore on the mesh, would the next step therefore be to actually paint some of these out in Photoshop?

- How would I increase the apparent depth of the treads? They don't seem to stick out much at the moment, at least nowhere near as much as the high poly ones

Thanks!

To better make the threads stick out is a matter of getting used to work with nmaps. When you know it's going to bake, you tend to exaggerate a lot of the shapes angles to work even on a flat surface. It's the kingdom of the 45 degree angle.

Baking an AO in you case will also help selling that little more depth.

Also, don't paint over your normal map unless you know what you're doing.

Originally Posted by PHaynes888

Ok, so following the advice of that thread above (cheers sprunghunt) I got rid of some of the wavyness, I think I may need to subdivide my low poly up a little more to get rid of some of the existing kinks. This is how it's looking currently:





I have some more questions...

- There are obvious artifacts on the normal map and therefore on the mesh, would the next step therefore be to actually paint some of these out in Photoshop?

- How would I increase the apparent depth of the treads? They don't seem to stick out much at the moment, at least nowhere near as much as the high poly ones

Thanks!

Did you do something weird here like add in more segments to your low after you baked your normals? You shouldn't be getting noticeable waviness on an object with that many sides.

Waviness etc: http://www.polycount.com/forum/showthread.php?t=81154

Nope, I added more segments to the low poly before I rebamed the normals though. Looking at the waviness it seems to be kinked at every poly along the outer rim on the low poly which is weird

what do the low wires look like?

Care to upload objs of the low and high? Something doesn't really seem quite right, you shouldn't get that sort of waviness with the amount of geometry you have there.

Also it looks like you might have your normal map loaded as a bump map or something, the shading doesn't seem quite right. Make sure the material type is "normal bump" and that you're not loading a normal map directly into the bump slot.

You're right, I've added it as a bump map, good spot I've just read up on this and saw this on a tutorial:

Now go to 3dsmax and open the Material Editor (M). Select a new slot and go to the Bump slot. First set the amount to 100 (the default is 30). Click on the None button and from the window that apperars select Normal Bump. Click the Normal slot and from the window that appears select Bitmap. Load the .psd file you just saved. There is one more thing you need to do to see the normal map in the viewport. In the Material Editor check the DX Display of Standard Material in the DirectX Manager section.

So i'll try that tonight

I'l also try to send you the OBJ files after work later or upload them here, cheers

So tonight I made some changes to the low poly, re-baked the normals and baked an AO map, also I fixed the bump/normal bump issue - somewhere along the line the waviness disappeared. So everything is coming together, think I'm about done with the normals for this now so thanks for the help everyone! Render is below, I realise the low poly isn't the lowest poly tyre ever, however as I only needed the low poly to help me unwrap the tyre (and I'm not trying to fit it into any kind of game budget) I'm happy enough with it:



Of course, if I do have any more related questions, I'll post again

There's a lot of extra edge looks you could easily remove without causing any issues. But that last bake came out really well.

Yeah you're right, I actually added a lot of edges to get rid of the waviness and some of the fifty-pending around the outside, I'm happy with how the tyres look now and as I said I'm not working to a budget so I might just leave them in

I think there is a lot you can optimize here and still get a nice bake. I think a big reason why you were still getting the waviness was that you added in more geometry, but it wasn't actually more round in some of the areas here. Remodeling it from a cylinder with a higher # of sides would probably help.

Also how you're doing the rim is rather strange, that should be welded and flow into the tire.

You should be baking with the entire lowpoly model there too, not deleting the mirror section. Just offset the UVS exactly 1 unit off the grid(will still work and you don't need to move them back). Otherwise you will get seams there when you copy in the other section.

I would still be happy/curious to take a whack at the low here, I think there are a lot of little things that you can really improve upon still, and if you keep doing them the same way in other models you're going to run into problems/unneeded headaches.

You should take EarthQuake up on his offer. He's always given solid info, especially with modeling and normal mapping. The guy knows what he's doing, and is willing to share.

Yep, I e-mailed him the files he needs a little while ago

Ok so, sorry it took so long to post, but I had a whack at the lowpoly here.

A couple notes: by simply starting with an appropriate amount of sides to the cylinder you shouldn't have any noticeable waviness. I think the waviness problem you had was from adding extra geometry, but not round geometry, to your mesh. I used 24 sides here which seems to do a great job, but you could bump it up to 32 if you really needed to view the tires up close, and still be way below the triangle count of your previous version.

24 or 32 are good numbers, because when you do LODS 24 becomes 12, then 6. 32 becomes 16 then 8. I always try to stick to easily divisible #s for cylinders.

I merged everything into one seamless mesh, you had two bits intersecting here wasting a lot of tris on things that wouldn't be seen, and creating extra uv seams/bake issues where the two objects intersect. You also had a random little detail modeled into the lowpoly(not sure what its called) along the edge of the rim which I removed, the normal map can represent this just fine.

I unwrapped the main chunk of the tire that would face the player onto on seamless island, this helps while texturing and helps UV distortion as well. I offset the mirror section which in this case is simply the treads by exactly 1 UV unit, this helps the object bake correctly as mention previously. Getting even UV detail is really important for consistency as well.





Low OBJ: http://dl.dropbox.com/u/499159/tyre_low.obj

This was baked in Maya but should look more or less the same in Max. You may need to add a little more geometry to the inner rim details to avoid smoothing errors in max.

Awesome, thanks very much for taking the time to do this, it looks really good . I'll download the .obj tonight and check it out. Do you mind if i use your low poly as my final low poly? I intend to attempt to learn from it and apply what I learn to the low poly for the rest of the car but I might as well not waste what you've done here, if that's ok?

I didn't realise i would be able to remove that metal clip from the tyre rim, I assumed that any geometry like this would have to represented in the low poly in a basic form, good to know!

Originally Posted by PHaynes888

Awesome, thanks very much for taking the time to do this, it looks really good . I'll download the .obj tonight and check it out. Do you mind if i use your low poly as my final low poly? I intend to attempt to learn from it and apply what I learn to the low poly for the rest of the car but I might as well not waste what you've done here, if that's ok?

I didn't realise i would be able to remove that metal clip from the tyre rim, I assumed that any geometry like this would have to represented in the low poly in a basic form, good to know!

No I do not mind at all, infarct I think its probably a good idea to look at them closely side by side to take in the differences.

With the little detail there, that sort of stuff is really what normal maps do best. Represent small shapes and details where there isn't much/any silhouette change. What you really need to model in is your larger forms, shapes, curves etc that affect the silhouette, because a normal map can't fake that.