UV Mapping AT-ST

UV mapping is the process of turning the outside of a 3D model into a 2D image. The 2D UV map is able to be exported to other programs like Photoshop, where it can be used to create the colour of the model. The UV map can also be used to create bump maps and specula colour maps to name but a few.

A good analogy to explain UV mapping is to compare it to tailoring a suit. The tailor has to map out on a flat piece of material where the different parts of the suit are going to be, the end product usually contains complicated shapes. The same process is applied to UV mapping but in reverse, you have the 3D product, but you need to make the flattened out version.

You should only really start to UV map when the modelling has been finished. Otherwise you may need to re-map.

The first part of UV mapping is to assign a checker pattern to each object of the model. The checker pattern will usually look stretched or compressed in some places. It wholly depends on what you are modelling.

Maya has several types of read- made UV map modes, Spherical, cylindrical, planar etc. They are very useful if your model contains polygon primitive shapes, like spheres or cylinders. Automatic mapping allows you to fine tune how many faces there are on the UV map. This can be very useful for simple shapes, the more complicated the shapes, for example a mixture of curves and planar surfaces, the more difficult the UV mapping.

For a more complicated model, it may be useful to select a set of faces you want to have as a face on the UV map. Then using the UV editor, manipulate the UV vertices to try and get the checker pattern have a similar amount of the same aspect ratio as possible. This will ensure that images and texture doesn’t look stretched or compressed.

When trying to achieve a similar aspect ratio to the checker pattern, it is advisable to change the scale of the UV’s on the UV editor to make the checkers smaller; with smaller checkers it is possible to identify a finer degree of deformation in the checker pattern.

Due to the nature of UV mapping it is very rare to achieve a perfect aspect ratio to the checker pattern, as long as the checker pattern as a close enough aspect ratio to each other, the textures and/patterns on the model shouldn’t look too distorted.

Modelling my ATST walker was a mixture of easy and difficult UV mapping. The legs for the most part are rectangular; therefore I used automatic 6 sided mapping. The problems occurred in mapping the head and feet sections of the model as they contained both planar and curved surfaces. I selected the faces of each part of the model that I wanted as a section on the UV map, and then used planar mapping. Then on the UV editor I arranged each set of UV faces so I could sew some of the edges of the map together, this ensures that a whole texture will stay on the UV map even if the texture is placed over the edge of 2 UV faces. The shape of my UV map meant I could only sew together a few edges, I ensured that the edges that were sewed were ones most likely to be visible.

Below is the final UV mapped AT-ST model with checker pattern.