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View Full Version : Help: Why shader appears on each face of poly?


ruukki
11-21-2005, 05:48 PM
Hi, this is probably something I should know already, but for some reason don't. I assigned a material on my poly mesh (a head), with a file as color. For some reason the file is projected on each face of the poly.

I know this has something to do with the mesh: I tried the same thing on a default poly sphere about the same size, and it worked like it should (i.e. repeated once over the whole surface).

Thanks for a reply, anyone!

lowkey
11-22-2005, 06:39 AM
Make sure that your UVs are all normalized to utilize the 1:1 texture space. That is: all pieces are laid out in e.g. the upper right square of the co-ordinate system. Everything beyond will be repeated.

ruukki
11-22-2005, 07:39 AM
I might be a bit blind but I don't seem to find a way to delete this message altogether. How is it done?

lowkey
11-22-2005, 07:42 AM
Can we have a snapshot of your UV layout? Did you actually do the unwrapping manually or just apply auto-mapping?

ruukki
11-22-2005, 01:53 PM
Hi, and thanks for your time already.

Here's what I have. I figure the image in the UV snapshot should more or less repeat on the face of the character, right? Now it appears to lay out there as if from a side or so.

Edit:
I didn't know the UV snapshot only takes with it the geometry (well pretty obvious though) - so I reproduced it in Photoshop. I hope it's still somehow visible. Everything's between 0 and 1 as it should be.

Edit:
Also, I added the moustache, hair and eyebrows (and later assigned a new material to them) when I had to capitulate. So, I don't expect the map to be exactly as it's on the UV editor - but not all about the place either.

lowkey
11-22-2005, 02:12 PM
Well, it's pretty hard to judge what might have gone wrong by just having a look at your shots. To be honest, I really don't know, man. Sorry. :sad:

ruukki
11-22-2005, 02:28 PM
So then - gotta have a look at it with a different model and see if it just repeats. Annoying but not the end - I like the Maya procedural texturing system enough, so it's not at all necessary to paint my textures. Still - it would be nice to know what gives. I've had this before, too, so if anyone's ever had this kind of problem please tell me how it went away.

Edit:

I did a quick test on a simpler model:
-assigned the same shader and checked what happened. The shader repeated here and there.
-I normalised UV:s, and the shader repeated only once on the surface.

I tested again on a different, more complex model: the shader repeated on every face of the mesh, with or without normalising UV:s. I also tried the normalising two ways, just to make sure: on the whole mesh, no go. On selected faces (all of them), no go.

So then - what's the workaround? Too deep for me. If someone's in the know, please share.

LehaS
11-23-2005, 07:00 AM
Well i m not UV mapping guru but i d like to suggest you to assign a basic Checker pattern instead of your file texture....you can then visually find problematic areas or even you could UVmap it from scratch...

Take care

lowkey
11-23-2005, 07:09 AM
Yep. leha_sokol is right. You should get your head around UV Mapping and learn everything about unwrapping, projections and how to create a working UV shell. In general, it works like this:



first creating several projections based on different parts of your geometry (e.g. arm=cylindrical, front face=planar, etc.)
then sewing the resulting UV shells together to create a UV Map you can paint on
It's important to maintain the 3 dimensional distribution of the polygonal proportions in the 2D map (to avoid textural distortion). So you might have to use the relax function a lot to keep it clean.

Good luck! :)

ruukki
11-23-2005, 10:57 AM
Hi, for once I can say "Yes, I have tried". As I said, the problem is not that I have (for instance) the moustache on the wrong side of the head, or anything of the sort, but this: The texture repeats in EACH of the faces of the mesh instead of repeating, for instance, once or twice or three - or even ten - times over the mesh.

Also (as I said in the last post), I did try the thing on a simpler model, with OK results, as you can read there.

Also - as I knew maps could be time-consuming to put just in the right place - I made the rest of the map one compact color and just left some variation on the face of the head. So I thought I'd pretty much make it with maybe one spherical and one planar projection for the whole thing.

To boot: I also checked the normal direction before I did anything with the texture.

But thanks anyway - I solved the problem by going a different route altogether. I'll have a look into this some other time.

lowkey
11-23-2005, 11:01 AM
Did you actually try to delete the current UVs and map them again from scratch? I can't believe this to be an issue with regard to the model per se. :shrug:

ruukki
11-23-2005, 11:05 AM
Hi, yes, and even took a different model altogether - seems that there's some problem with more faces. I did it on a maybe 20-30 face mesh and no problems.

LehaS
11-23-2005, 11:18 AM
Sorry if i didnt pay attention that all your faces have exact same texture without repeating

...Well ..then the most logical reason why you could get this problem is that you mapped your model for each face separately....as i told before i dont use UVs that much so i cannot direct you to the right button....i think you should maybe map your model on "object" level , not component......i dont know how it could happen in your case since by default when you map something it creates single UVmap for all the model........please someone correct me if
i m wrong...

lowkey
11-23-2005, 11:19 AM
Well, I don't know, man. Maybe you have accidentally set the UV repititions in the texture node? Usually when texturing on component level, the texture should be shared by the group of selected polys at least.

Dunno really. Sorry! Why not screw the model all over! :P

ruukki
11-23-2005, 12:00 PM
Hi, and thanks both. The solution was very obvious, in fact.

1. I normalised UV:s
2. I applied spherical map over the whole mesh (it's only a head, so roughly spherical).
Presto!

Now I suppose I can start tweaking the UV:s further, as I have the basic placement in some proportion.


Why I didn't think of this before: my test with a low poly mesh worked fine right after normalising UV:s. So I never thought a higher resolution mesh might call for a specific way of doing it (well actually I did but didn't have any idea of what it might be - your suggestion of spherical mapping made me try it).

lowkey
11-23-2005, 12:28 PM
Wow, nice! I'm glad you finally did it. Let us know your progress. ;)

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