When creating characters in 3D, modeling is often enough to get you a basic shape,
but modeling every minute detail of an object is typically not an option given the limits of computing power.
You can capture these details more efficiently with a 2D image projected on the surface of your object,
also known as a texture.
Texturing a flat surface is fairly straightforward. All you need to do is project an image onto it.
However, imagine trying to project an image this way onto an organic surface.
What direction would you project from to get overlapping areas like these head ridges or inside the mouth?
And how would you account for depth?
In these cases we need a way to map our 3D object in a 2D space through a process known as UV unwrapping.
Imagine peeling off your model's skin, laying it flat on a canvas and painting on it, and then placing it back again.
This flat canvas is also known as the UV space.
For those that are unfamiliar, UVs are special points that overlap with vertices,
and represent those spots of the 3D model in the 2D UV space.
Because of this correlation, it is important that any model we want to texture has a sensible, even vertex layout.
If you are unsure how to layout the vertices, check out our three part tutorial on modeling with proper topology.
The next thing you might notice is that trying to unwrap this entire head could get a bit complicated.
Can you imagine what kind of shape it would even unwrap into?
One way to tackle this challenge is by breaking this complex shape into several simpler objects
that will each unwrap into neater, more manageable shapes.
Change to Face selection mode and then select all the faces that make up the neck.
We've included a quick selection set to make this a little easier.
Now shift select the entire mesh and then select Mesh > Extract, to extract those faces to their own mesh.
Now would be a good time to delete your history.
Use that same method to extract the crest, lower jaw, throat, and tongue into distinct objects.
Your main dragon head should now be comprised of 6 separate objects.
This is in addition to the upper and lower teeth, their gum lines, and the eyes which were already separate objects.
Now we have several smaller shapes to texture. Let's start with the neck.
Open the UV Texture Editor. This shows us a representation of our 2D UV space.
In the main workspace, select the dragon's neck.
This, unfortunately, is the current layout of our UVs. The process of modeling has jumbled them beyond recognition.
This can be made even clearer if we apply a checker pattern texture to our neck.
Notice that the squares are inconsistently laid out with huge patches missing.
Ideally we'd like this pattern to be mostly uniform across the entire neck surface.
Rather than attempt to unravel the existing UV layout, let's replace it with a new one.
Select the Create UVs menu and take a look at the different mapping options.
You may be tempted to try an Automatic Mapping first.
However, if you do this, notice that the neck is suddenly broken into many pieces.
You can see this more clearly if you dim the background image.
This UV alignment makes it difficult to figure out how these UVs connect to one another.
Additionally, notice that the checker pattern is still not very uniform.
We could instead try a planar mapping, which seems to give us the uniform pattern we want.
Until we look at the top and bottom of the neck where the squares are stretched.
Think about a projector casting an image on a non-flat surface.
Any surface with depth relative to the projector will get a stretched version of the image.
If you turn on the Shaded UV display, the UV areas highlighted in purple indicate
that the UVs at the front and back of the neck are overlapping, which is generally not recommended.
Unfortunately, any other projection type will also result in overlapping UVs.
To solve this problem, we'll need to unfold the UV mesh.
When unfolding a mesh, the first thing we'll need to think about is where to put the seams.
A seam, much like a seam on an article of clothing, is the area where the UV mesh is allowed to break away from itself.
In general, it is very difficult to get the images on two sides of a seam to line up perfectly,
so you want the seam to be as hidden as possible.
In this case we really have two choices. Either the top or bottom of the neck.
Since the bottom of the neck will be prominently covered by the dragon's long skull, let's place our seam there.
Select the edges along the gullet and in the UV Editor select Polygons > Cut UV Edges.
Now try selecting the Unfold command. Notice that the UV mesh doesn't change.
In order to unfold this, we need a pinned point that won't move.
If you think about this like unfolding a tablecloth, you need a place on the cloth that will stay put
otherwise you're just going to pull the entire cloth with you.
Let's change our selection mode to UV and select a UV on the back of the neck.
Now in the Unfold UVs options, set the Pinning to Pin selected UVs.
In the UV Texture Editor, the shape unfolds nice and evenly.
You can see exactly how the shape lines up with either side of the neck.
Looking in the viewport, you can also see that the checker box pattern is mostly even along the entire neck
except for the front gullet where we chose to put our seam.
Now that we have a properly unfolded UV mesh, we'll need some way to transfer this mesh
to our favorite 2D authoring software.
First, select all the UVs and scale them to the bottom corner of the UV space.
Notice that we're leaving enough space for the rest of the head components which will come later.
Now select the UV Snapshot command.
Let's crank up the resolution a little bit to make this easier to work with.
Additionally, you may want to change the file type depending on what your 2D authoring software of choice supports.
Maya outputs your UV mesh as a picture file that you can use
as an overlay in your 2D authoring software to create a texture.
In the next lesson we'll tackle texturing the rest of the skull, and then recombine everything into a single object.