UV Mapping – Tutorial.

This is a short tutorial on UV mapping a model. The model selected was created by Sean Hall as part of a project we are working on together.

I do not claim to be an expert in UV mapping, but over the past few years I have learned a little bit about the process of it and have developed a method which I am happy with using. It is through this tutorial that I aim to pass on this knowledge.

Lets take a look at the model that is going to be unwrapped.

The first thing I want to do, is to divide it into its component parts, look for repeated areas and separate them into different layers. Ideally I want as seams as possible as this reduces the risk of errors and gaps in the map, but I also want to prevent stretching and squeezing of the textures as both of these make it harder to manipulate the textures later in the process.

So firstly, I’ll take away the most obvious part. The centre piece. No matter how I unwrap it, if I leave it in the centre the map will be a mess. During this process, the spouts at the top of the model are deleted, except for one, as they are all copies of each other and will have the same texture, it makes sense to only do one of them.

Within this top part of the model, there are 4 separate geometries, the spout, the square part at the bottom, the curved middle, and the square part at the top. None of these parts are joined together, so it doesn’t matter that they will be separate in the UV map, as there will be no seam.

So now we have 5 segments which need mapping. I will be using a tool in Lightwave called plg-Make-UV-EDIT so that I can create my own customised UV maps by selecting edges. (I will not be explaining how to use this plugin, if you want to learn how to use the plugin I suggest you watch some tutorials.)

The first component I will unwrap is the base of the model. I will take the large flat area as the centre, and then split it at the corners.

Note that the blue lines are where the splits will be. While it is of course possible to do this with no seams, this method allows there to be very little, if any stretching of the UV map.

You will notice that this section is taking up the whole of the UV map a present, this isn’t a problem as it can be resized later to allow the rest of the segments to be fitted on.

The next section is very simple, and only requires one cut.

And gives the following…

for the base section I used the following cuts,

this is so that the UV map is slightly less stretched, and has less curves in it. This saves space and makes it easier to add texture details in photoshop later.

Since the top part has another flat surface, I will do the same as with the base of the fountain.

Now for the final part of the model, the spout. The spout is actually two parts put together, but can be treated as one.

This piece was a more complex geometry than the other parts, and so required a bit more forethought as to how to get it to unwrap with the least amount of stretching and while maintaining the fewest seams possible.

The final part of this exercise is to put all the parts together on one UV map so that they can all be drawn together. There are a few rules that I like to keep to in this exercise:

  • Keep parts roughly to their scale on the object
  • Parts which require higher detail, in this instance the spouts, should be larger than the rest
  • Make sure no parts are overlapping, and all are within the bounding box
  • Leave a little space between each section
  • Dont change the orientation of the sections if at all possible

The final UV map looks like this.

You can of course wiggle sections about to get the maximum out of the space, but for the purposes of this tutorial, it is enough. By having nice obvious sections, it is much easier to create textures for models. If you have the energy, it is also very nice to open Photoshop and write by each section exactly which part of the model it relates to, this doesn’t take long, and is really nice for the person creating the textures for your model.