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Naisart
02-23-2003, 08:08 PM
Hi,
I have some questions regarding low poly texturing. I was thinking about creating a low poly character (that could be used in pc games) and these questions came to mind:

1) How many texture maps should I use? Like one for the head, and one for the rest of the body or does this depend on what the model is going to be used for?

2) Which size should the map/s be? And why are they always 256 x256 or 512x512, etc..?

3) I have seen these UV maps (looks like map type is atlas), and they look completly confuseing. I mean, how can you tell which part of the map is what on the model? (hope you know what I mean :) )

Thanks in advance!

Jonny Bubonic
02-24-2003, 01:21 AM
Hi Mumphy

Well, for a PC game :

Taking Unreal Tournament 2003 as a guideline, you could use 2 textures at 1024x1024 each. This varies from game to game, but this is a nice size to work with if you don't really have restrictions. One for the head (which is a bit excessive, but what they hey), and another for the body, or whatever you like. It all depends on how you layout your UV map.
You can use textures that are to the power of two, eg. 256x128, 512x512 etc. They don't all have to be square, as long as each side is a power of two.
When you map your own model, you'll know what's what on the UV map :) If you get lost or forget, you can select the UVs on the map and they will highlight on the model, showing their position. Mapping is a bit of a skill in itself, so if you don't know how to do it , take a look for some tutorials ;)

HarlequiN
02-24-2003, 01:47 AM
The number of Texture maps you use would depend on what you're texturing, and what you want to do with it. In engines that use shaders for example, you might want to have the poly's that will eventually have a shader on them on another map, because the shader may require those poly's to be drawn multiple times, which can slow the engine down. That said however, using too many maps can also slow down the engine, so it's a ballencing act. For games on consoles such as the PS2 as another example, it can require a lot of maps, as each map's size tends to be limited by the way the engine's handle accessing the hardware.

Again, the size of the texture varies. For PS2 you might be limited to 128x128 max, while on a PC it can go anywhere up to 1024x1024 or higher. The reason for the particular sizes is that computers work best with multiples of 2, so the patter goes 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 and so on. As Johnny said though, the limitation is to the numbers you can use in any given direction, rather than both at once, so 32x1024 is an exceptable size in most engines (if you'd want to use that size).

UV maps can hurt the brain the first time you see them, but you soon get the hang of spotting general things ("oh, that's an arm, and that's the face" etc.), but for odd bits you'll need to check them. To check them you can just paint each segment a different colour, and then test it on the model, If the arm is red, then the bit of the mesh you painted red will be the arm - makes sense :)

Anyway, good luck.

AgentX
02-24-2003, 03:40 AM
Ok, here is what I know. I hope it helps:

UV mapping is tedious, but worthwhile. And yes, when you UV map your own character, you know what each piece is, and how it is shaped.

Regarding the textures...it is ENTIRELY dependant on the programmers desires. I am working with gamers at the moment on a few different games, and my texutures sizes are dependant on what they can handle, and want. So it is impossible to answer that question, becuase it requires you to be working on a real project. I would suggest if you want to do it for fun/demo reel, use a 1024x1024 texture. It looks good, and is not outragously big. Besides, it you can always make pictures smaller! :)

Typically textures at a power of 2, 64x64, 128x128, 256x256, 512x512, etc... This originally back in the day was becuase game engines read square pictures fastest. However, as with everything else, it changes as time continues, and as the designers specify. I know of some games that take 128X512, and this is becuase they way they coded their engine that size is read fastest. It is all about speed in games.

Anyway, I hope this helps somewhat. Good luck.

chrisdejoya
02-24-2003, 06:46 AM
Mumphy: have you tried 3D paint? There's Maya's built-in, Deep Paint, Deep Character, Cinema 4D > Body Paint...tons of choices, but the price is prohibitive.

You could pick up a copy of Unreal Tournament 2003, and install Upaint, found on the 3rd disc. Export your model to the .PSK format (using ActorX) and load it up in Upaint.

Often the idea is not about creating the polished final skin in 3D paint, but to rough in all the colors as well as you can, including highlights, shadows, etc. Then make a last pass over it in a 2D paint package. Deep Character's workflow is nice, because you have access to both 2D and 3D views at once, and the paint looks fantastic.

Just make sure that UV is laid out well. ;)

have fun,

Naisart
02-24-2003, 06:57 PM
Thank you all very much for taking the time to reply to my questions!, they have clarified a lot.

I understand now how I should go about texturing the object, but some other questions came to mind when I started modeling yesterday.

1) When modeling, do you fist model with quads, and the when your finished with the model, you tripple the polygons and then tweak it?

2) Does it matter if the polygons are quads, I mean, should you still stay away from any polygins that arenīt quads? It shouldnīt matter since all polygons will be trippled anyway, right??

3) Anything else to think about when modeling low poly objects?

Itīs a lot of fun to model low poly and thanks again for all the help!

sic1
02-24-2003, 09:35 PM
1) If you're talking meshsmooth... then you may want to keep on eye on your poly limit. Otherwise, it's wise to start off modeling with a cube, and make sure you can see the individual edges. Turning the edges and optmizing can be very helpful to keeping a cleaner, more efficient mesh.

2) As far as I understand...3ds max works with triangles, and maya works with quads (yet there is an option to triangulate). The triangles are important, as the engine will render them. Polys are usually made up of two triangles, or faces (Except those really odd ones :) ).

3) I don't know how much experience you have with modeling low poly... but an important step is definitely planning.

Jonny Bubonic
02-24-2003, 10:45 PM
Tripling is a lightwave term I think, also known as triangulating. "Triangulating" is the jargon that most modelers will be familiar with, just to sort out any confusion.
As for modeling, only high-res models need to be kept strictly in quads, as these smooth much more predicably. For low poly stuff, use a mixture of quads and triangles as you see fit. Quads are easier to visualise, and make a "cleaner" looking model, but they can be wasteful. For areas like the shoulders, knees and elbows, try to model using a hex-pattern made of triangles (also known as geodesic modeling). I'm really pimping this technique, but only 'cause I think it works so well for low poly stuff that has to deform well when animated. Check out this thread (http://www.cgtalk.com/showthread.php?s=&threadid=21507) for some pointers and an illustration of what I mean by this. It's pretty tricky at first though, so you might want to stick with modeling mainly in quads 'til you're comfortable. You should triangulate your model at the end for in game use, and turn (flip in Maya) the newly created edges so that they fold properly when deformed by animation. For presentation, though, you might want to leave your model un-triangulated, as its easier for others to see how it's been constructed (for criticism, if you want it;) )

Naisart
02-25-2003, 04:03 PM
Thanks for the help! Yeah, I read tat thread and that method seems really cool. Looks kind of complicated to learn but everything is hard in the beginning :).

A questions: I have made UV (atlas) maps for my model, when making maps for photoshop, should I just make it as large as possible on the screen and then print screen and paint on it. I have textured before but does this method work well with UV maps?

Thanks in advance!

Naisart
02-25-2003, 04:28 PM
Some more questions:

1) I printed the UV map off the screen and then I took it into PS and wrote on some parts just to test. When I applied it, the text had gotten mirrored and didnīt show up in places. I cropped the map before applying it. Why is that happening?

2) After I have used print screen, should I then resize the map in photoshop to the size I want it to be, for example 512 x 512?

3)When I resize it and for example put the witdh in as 512 the height doesnīt say 512 and I understand why but how can this be fixed? I mean doesnīt this result in a streched texture?

4) When I created the UV map for the body, for example, I just made a new UV and used Atlas as map type, is this the correct way to do it?

Thanks in advance!

Jonny Bubonic
02-25-2003, 09:00 PM
Hmm..I take it you're using lightwave, as these terms (atlas map) don't sound too familiar. It sounds like spherical mapping, which is not really what you want to be doing, in most cases. Is there a type of projection called something like "planar" or "single plane" or "flat" projection? That'll be the one you need the most. Like I said before, mapping is an art in itself, so you really need to find out how to do it right. It's not easily explained without illustrations, so have a look for some tutorials for whatever program you're using. When you're finished mapping a character, your UV map should end up looking a bit like a tailor's pattern for clothes making, with the seams in places where you wont see them easily.

As for exporting your UV map, "print screen" is a pretty crude way to do it. Maya has a function that'll save out your UV map at exactly the size you specify, and there's a plugin for Max that does the same thing. Check the manuals to find out if there's something like this for your program (which you really need to mention if you want advice specific to your 3d tools).

Good luck dude,
-JB

Naisart
02-25-2003, 10:07 PM
Yeah, iīm using lightwave. Yep, there is a type called planar but if I use that on the whole object it doesnīt come out right and if I want to use one map for this I have to make some kind of UV which will display the entire model, which atlas does.

I often see these maps that contains all parts of the object on one map and then the person has painted on that map and iīm basically just wondering how to make such a map correct, so that I can paint on it and then how to apply it correctly. Any ideas? and thanks for helping me out so far :)

Jonny Bubonic
02-25-2003, 11:46 PM
You have to make several planar maps, tweak any stretched UVs, sew up some seams and lay them all out on the 0 to 1 square in your UV editor. You can't just do one projection and leave it. :) I'm working on a model now, so when I get to the UV mapping stage, I'll try to show you what I mean. Could be a few days though.
Try this in the mean time :
Select the faces that make up the FRONT ONLY of the torso. Do a planar map of these faces and look in your UV editor. See what you've got? Do the same for the back of the torso. Layout the two pieces side by side in the UV editor. It should look something like a sleeveless t-shirt, in two halves. The idea of mapping is to get the UVs to resemble as close as possible the vertices on the model, so if you've got 4 verts making a square on the model, you should arrange the corresponding UVs into a square too. If they're squashed into a rectangle or deformed in any way, your texture will be too, when you apply it. Try to think of it in terms of cutting pieces out of your model, and squashing them out flat. Like taking an orange, peeling it and squashing out the peel, or like the classic atlas, which is an unfolded sphere.
I hope that made some kind of sense...its pretty hard to explain without examples :D

Cocefi
02-26-2003, 02:57 AM
Hi there,

Maybe this old thread would help:
Clicky (http://www.cgtalk.com/showthread.php?threadid=14607)

Naisart
02-26-2003, 02:12 PM
You have to make several planar maps, tweak any stretched UVs, sew up some seams and lay them all out on the 0 to 1 square in your UV editor. You can't just do one projection and leave it. I'm working on a model now, so when I get to the UV mapping stage, I'll try to show you what I mean. Could be a few days though.
Try this in the mean time :
Select the faces that make up the FRONT ONLY of the torso. Do a planar map of these faces and look in your UV editor. See what you've got? Do the same for the back of the torso. Layout the two pieces side by side in the UV editor. It should look something like a sleeveless t-shirt, in two halves. The idea of mapping is to get the UVs to resemble as close as possible the vertices on the model, so if you've got 4 verts making a square on the model, you should arrange the corresponding UVs into a square too. If they're squashed into a rectangle or deformed in any way, your texture will be too, when you apply it. Try to think of it in terms of cutting pieces out of your model, and squashing them out flat. Like taking an orange, peeling it and squashing out the peel, or like the classic atlas, which is an unfolded sphere.
I hope that made some kind of sense...its pretty hard to explain without examples
Yeah, makes a lot of sense and thatīs actually how I do when I texture other stuff (high poly) but I didnīt know how to apply that method to make one UV map. That thread explained it all, thanks a lot CCF! and thanks a lot Jonny for all the help!

Naisart
02-27-2003, 04:17 PM
Some more questions :) :

1) Is it ok to use smoothing on the object?

2) When makeing the UV map, is there someway to make it for only half of the object and then mirror it? (my model is symetrical)

3) When I make an UV for a part, I then resize it and move it to one corner (as it says in that thread), but wohnīt this cause the textures to strech later on when I have painted the texture map? How can I resie it properly?

Thanks in advance!

Jonny Bubonic
02-28-2003, 01:18 AM
Hi again :) Sounds like you're making progress.

When you talk about smoothing, there are two kinds. One dramatically increases the poly count, 'cause it adds loads more geometry to make an object rounder. The other way is to adjust the vertex normals of your object, which only make it look smoother. This is the one you want for game models. In Max you create "smoothing groups" and in maya you "soften/harden normals". See if there's something that sounds like either of those in lightwave, or ask on the lightwave forum how to do it.
For mirroring your UV map, in this case just cut your model in half (because it's symmetrical), then mirror it. The UVs should be mirrored too.
When you resize your UVs, have all of them selected for the area you want to adjust. Just make sure you use a uniform scale when you scale them up or down, so that they remain the same shape.
Hope that helped :D

sadist
02-28-2003, 07:06 AM
3) Generally I apply the same co-ords to the entire mesh to keep everything the same res. From there I'll scale individual sections that need more detail, or maybe just to fill the gaps a little :)

Naisart
03-01-2003, 12:23 AM
Ok, I did as in that thread and made a lot of surface parts (http://www.cgtalk.com/attachment.php?s=&postid=130219 and I also made three UV maps altogether for all the parts and my question is now:

How do I make one surface for all the UV maps ?, because as it is right now I have to apply the texture map I make on every surface. It works fine but this means that I have to apply the texture map to every surface I have made, is this ok to do ? Itīs still only one map that I am useing (well three as I made three UV maps?.

Thanks in advance!

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