Question about UV Layouts and Scale

Stinkhorse

So I'm getting my feet wet skinning and one question I keep running into, but keep having to shrug and push on over, is one of scale in my UV Layouts. First off it drives me crazy when I unwrap a set of objects and their shapes aren't kept to a constant size. The shapes that come over bear no sane resemblance to the ridged structures I'm putting together. Is there any way to correct for this?

If there isnt a way to correct for it how do you account for it when you're laying out your UVs? How do you ensure that there's a correct scale from one UV map on one model to the next, especially if you're making a bunch that use roughly the same textures?

ZacD

User checkerboard textures after laying out the UV map.

Stinkhorse

Ohh that's a good call. Thanks!

Stinkhorse

But still is there a way (I'm in blender) to ensure that the UVs will import to scale from the model they come from?

Stinkhorse

Holy crap, that checker texture is helping a crap ton. I didnt realize how off I was when I was laying these things out previously! Thanks ZacD!

Shuriken UK

Yea I think all you have to do, is make sure the general size of the checker board is the same on all the parts, in relation to their UV "islands". I think its even better to think about what parts of a model are most important, and scale up their UV islands more, making their checkerboards smaller, which, in turn, gives them more texture space. I THINK thats how it works anyway. I've made a lot of models, but I'm still kind of wet behind the ears myself when it comes to a lot of things.

passerby

in blender there is a option called Average UV islands Scale, it does exactly what you want, and if your using the default keyset, it;s on control+a in the UV editor.

and the checker board is always good, can let you see scale differences, and makes stretching very obvious.

also, if you make a new image in the UV editor in blender, than press N to bring up options, you can choose between 2 different styles of checker grids, that blender genrates just for this purpose.

JamesWild

One thing I've found more useful than a checker map is a texture of noise. It allows you to see exactly the pixel density and stretching, whereas problems can exist within the boundaries of a checkermap.

Stinkhorse

@Shuriken UK:
Thanks for the tip, getting everything scaled has been much easier. Also I think I understand what you're talking about with the scale for importance. You need to make sure that the scale is done on powers of 2 to make it work the best right? Like if you're working on a purely square object, and have have eight checkers on a piece that's important, you'll want 4 checkers pieces that aren't. That way the scale down is as clean as possible. Something like that...
That could be a garbage assumption though.

@Passerby:
YES! That auto scale was exactly what I was looking for! You just saved me a huge amount of time and headache. Thank you so much!

@JamesWild:
Hey that's also a good idea. I'll try that out.

Stinkhorse

So initial excitement may have been premature. The grid is good for avoiding stretching, but I'm finding it seems to encourage micro adjustments (huge time waster). Worse, positions that reduce stretching seem to not be the same from geometry piece to geometry piece. This means that textures that I make for one object dont hold to the next object.

I'm pretty sure I'm doing it wrong in other words.

A strong use of the average islands tool is next, though I'm already suspecting after a few cursory uses it's not the tool I'm expecting it was.

Neox

JamesWild wrote: »

One thing I've found more useful than a checker map is a texture of noise. It allows you to see exactly the pixel density and stretching, whereas problems can exist within the boundaries of a checkermap.

Is a checker, has circles on it, as we are better recognizing circular shapes and has a 1px checker on top showing you, your pixeldensity

Stinkhorse

Oh wow nice! I'm going to try that out right now.

Update: Neox's grid just solved one of my problems almost instantly. The circles combined with the granularity do provide a scale of feedback that the checkers simply weren't. Thanks a bunch dude!

ZacD

I also like using this one to check for distortion, I tend to tile it a lot more though.

http://www.anthonycabula.com/wp-content/uploads/2011/02/CHECKERS-5.jpg

Neox

ZacD wrote: »

I also like using this one to check for distortion, I tend to tile it a lot more though.

http://www.anthonycabula.com/wp-content/uploads/2011/02/CHECKERS-5.jpg

oh also a nice one! though i think it has too much contrast - but these days we don't tend to waste as much time unwrapping as years back, when i did the first version of mine. 8 years back it almost took longer unwrapping than modelling and texturing, and everything with a high contrast would just hurt the eyes when staring at it for hours :X