Game Development Reference
In-Depth Information
map which has only two coordinates. For the sake of clarity, these two coordinates
are marked as U and V ( U = Xtexture, V = Ytexture ), rather than simply X and Y.
UV mapping of the Astronaut 3D model
Paper toys are not made of individual slices, but of elements connected together.
There are lines of seams and lines to fold. The unwrapping has the same principles;
some edges of a model must be marked as seams, other ones will be calculated as
fold lines. The tricky part is that for the best result, you should define all the seams
manually by selecting the appropriate edges one by one. Before that, you should
imagine in your head how a 3D element (for example, an arm) can be unwrapped
into a series of connected flat images. If the element is complex, it can be split into
several separate fragments. Remember that a good UV map is not a conglomeration
of abstract geometric shapes, but an image where the elements of the model can be
easily perceived and read; this is the head, here are the fragments of the boots, and
so on. Such a rule helps to create the texture right. In some cases, several takes
are needed to unwrap the 3D model correctly. After each take, you look at the result,
notice some error, fix it, and try to wrap the texture again. An unobvious feature of
UV-mapping is the visual testing of the mesh geometry. If there are some problems
such as double vertexes and sharp edges, the UV-map can demonstrate that; some
parts of it will be lacerated.
To create a texture based on a UV-map, the map's layout should be exported as a
raster or vector template. Blender has a special menu option for such an operation:
UVs | Export UV Layout . After that, the layout can be filled with graphics.
3D engines in games required models in specific formats such as OBJ-documents.
There should not be any lights, cameras, or incidental geometry in such files; oth-
erwise, an error or visual glitches may occur. Besides the main geometry, there can
Search WWH ::




Custom Search