This is the first tutorial I make because I dont want to se my friends sitting for hours to days on end dragging UV points and merging chunks together just to get a Stretched and overlapped result.
I will try to simplify the steps of UV mapping as much as I can so that beginning users can benefit from this tutorial to. I will demonstrate all the steps on the hand Iv just recently modeled for my site, if you wanna have a go on a more complicated model (like a whole person), I suggest you scroll down and read the last step first.
Lets first begin with what is UV mapping? UV mapping, is the process that takes your 3D model and unwraps it so that you can Paint over it with a 2D program.
Before You start, the things you always ned to kep in mind while UV mapping your models are as follows:
OVERLAPS – Overlap means the UV surface goes ontop of itself. Usually, you will want to have zero overlaps by the end of the process so that you can Paint your texture over the entire surface of the model separately.
STRETCHES – Stretches happen when you map a certain part bigger or smaller than its relative size. To avoid having Stretches, it is always recommended to work with a checkers map on your model and make sure the checkers stay square.
SEAMS – Seams are where your choose to Cut your 3d model so that it can be unwrapped into 2d. You will always wanna have as few seams as posible in your end result because it will make it easier for you to texture your model.
Basicly, the program comes with plugins that will directly export your model from your 3d program (Max,Maya,Xsi and LightWave) to DUV and back, but sometimes it doesnt work.
When direct exporting doesnt work, you will have to export the model yourself. After some research, Ive discovered that. OBJ is the best format to kep your models geometry unchanged. When you export your model, make sure you kep the faces as polygons. Id also recommend you check the exported model yourself, to make sure the geometry didnt change.
Note that in DUV, you can always save your progress into an. OBJ file.
OK, so youve got your model into DUV, lets first make some settings so we can se the Stretches later on: Right Click on the right viewport, wireframe/ uncheck the show wireframe and also check material override and uncheck texture smoothing.
Now you are set to begin. The first step you ned to take is to Apply a planar map to the model: Click select / all and then try planar 1 or planar 2, one of them ususally finds the perfect planar map to start with, but if you wanna do it yourself, open the Interactive tab and use the interactive plane.
Getting rid of the overlaps and seams.
Unless you have an open mesh, you will always get overlaps from starting with plannar mapping. To get rid of the overlaps, we will use one of the more powerfull tools of DUV – LIFT. Lift will take all of the Backfacing (the overlapping UVs), flip them and place them to the right of the UVs. Before you use it, make sure you rotate your UVs using the fre transform tools (under edit), so that you can determine where you want to place the seam you will get rid of (which will always be the right side of your UVs, before clicking Lift).
The next step would be to select the shared UV points and Join them to get rid of more of the seams for easier texturing.
Id reccomend brigging the (show) wireframes back for this step. Using the select tol, select all the shared points on one side (id recommend using the zoom and pan tools here to be precise), the selected shared points will turn pink on the other side. Now select the pink points on the other side (this will require much less precisión because points join only when the 2 shared sides are selected). Make sure u do not select shared points that are not betwen the 2 chunks because that will cause unfixable problems later on.
Now hit join the seam is now gone be you end up with a very Stretched part in the middle. It will be fixed next.
Relaxing and final adjustments.
When you first applied the planar map and then lifted, it semed like there are almost no Stretches but there are. Because anything that isnt exactly in front of the plane will have a little Stretching. This part will show you why DUV is such a powerful tol, the next step will be to select all the points again, and hit Relax, look at the magic, you now suddenly se the checkers become even squares and the Stretching almost completely disappears.
Note that you got some control over how the relaxing works, and its often god to try it with diferent área grid values until you
e satisfied with the result.
By now your model should be left with very minor SEAMS, STRETCHES and OVERLAPS, and this process should have taken you less than 5 minutos.utes.
You are now 80% done, this is the part where you fix by hand local problems and Cut and rejoin points according to how you plan on texturing your model. This is the part that i recommend doing back in your 3d program. Note that, DUV ofers some more powerful features such as software selecting points and relaxing local áreas.
Now its time for the much more fun part of texturing your model. But how can you tell which part of your texture goes to which part on the modelé
For this you ned to take a UV snapshot. Id recommend making the wires white and the background black, that bien you can always use it as the top layer in Photoshop (or any other 2d prog) with Screen blending mode, for MAX users, i also recommend a freeware plugin called TEXPORTER, it can take a UV snapshot in a more graphical bien which sometimes can help when painting your texture.
You might say: Of course its easy, you just mapped a hand, not a complex model.
Mapping a complex model requires one more step before starting and its to break your model into several parts. This process is a bit diferent in every 3D program so i wont go into details. But just note that this is the step that let you determine where the seams will be. After this process, you will ned to map each part seperately pretty much the same bien as explained above.
I mapped my dragón in a couple of hours using this technique.
I hope this tutorial was helpful for you.
Dont sit on those UVs for days EVER AGAIN.