This
is one of the most interesting steps in the image creation process. You can have
the model that is accurate and detailed but if it doesn't have the right textures
and lighting it can look totally flat and uninteresting to the viewer. There are
two ways to do the texturing. You can do it with procedural textures or with image
maps.
The
first method will give you more computer generated look, but it will use a small
amount of memory. The procedural textures are calculated using the mathematical
algorithms behind it. They can be divided in two categories, the 2D procedural
textures and 3D procedural textures. To map the 2D proced. on polygonal objects
you will need to set the right UV maps, or you can project it on model. On the
other hand if you are using the 3D procedurals, since their calculations are dependent
on the 3d point in space, you don't need to create UV maps.
Initial
UVs after the modeling process... very very bad, I need to fix this. ;)
Tools
used:
Just
switched to UV view to see this mess...
The
second method of texturing by using image textures will give you very realistic
appearance of materials, but it will use more memory. Of course you need to have
the texture collection, or you can photograph textures by yourself. If you decide
to use the texture collections, one of the best choices will be to purchase one
on internet, like the 3DTotal Textures CD that I've used in my image. For now
there are 3CDs with 3DTotal textures with the collection of color and bump maps.
The textures from that CD's are also seamless, that means that you will not see
any seams when they are repeated over the surface.
When
texturing the polygons with image maps, first thing you have to do is to define
the UV mapping of the objects. For this kind of objects, like building, defining
UV mapping is not too difficult to do. This will be shown in next few steps...
as an example I will use the main building part.
As
you can see from the picture on the left, the initial UV map, after I've finished
the modeling part, was not what I wanted. This is surely not something intuitive
on which you can paint the textures on in photoshop. But, there are tools to do
UV unwrap, so let's use it. I've made one decision when I came to process of UV
mapping of this building, and that was that I will define the UV map for only
two walls that are pointing towards the camera, since other walls are hidden from
the viewer. As you can see that is, when looking from front, the left wall with
window in it, and front wall with door and windows. Don't worry about the top
part where roof stands, it will be covered with the roof object. So, to create
the UV maps of these surfaces I have selected them (select faces) and then set
the planar mapping on them. These two examples (pic2 and pic3) show just that.
I've selected the faces for the side wall, went to options of Planar Mapping,
turned on the Fit to Bounding Box, selected the mapping direction which have to
be perpendicular to the faces, and that was it. This was also done for front wall.
One more thing, If you try to do the selection for the front or side wall, don't
forget to select the faces of the door and windows.
Selected
the faces from side wall and created Planar Mapping.
Also
for the faces at front wall, created Planar Mapping.
Tools
used:
Edit
Polygons > Texture > Planar Mapping
Tools
used:
Edit
Polygons > Texture > Planar Mapping
The
UV of two walls after the projections. This should be placed next to each other.
Tools
used:
Only
switch to UV window.
Now
the next step. The UV map at this stage is still not finished. What I did in the
steps above is that I got the usable proportions (or projections) of the front
and side wall, so when I paint the textures on them, they won't be distorted.
But, the projections are overlapping as you can see in the first picture below.
This must be fixed. There are also the other leftbehinds of the other polygons
for which I didn't define the mapping, but I didn't bothered with them because
they will not be visible in final picture. What I've done now was that I've put
side by side the UVs for front and side wall. It is possible to do this by hand,
but it is also possible to get a little help of layout tool. I did it with the
layout option for which I set the Along U and Uniform Scale attributes. After
I've clicked on Apply, what it did was that it layout the UVs like in second picture.
The next step I've made was that I moved UVs for front and side wall from the
top right area of UV grid to the bottom area and scaled them to fit the area from
0 to 1 in UV space (pic 3). At the end I selected unwanted UVs for other walls
and moved the apart from the top right side of the UV grid, and then I moved wanted
(front and side walls) UVs to the top right quarter in the UVs grid.
UVs
after the layout tool was used. I would only use the first two parts on the left.
The
UVs of two important parts were selected, moved to the bottom, scaled, and after
this moved to the top.
Tools
used:
in
UV Editor > Polygons > Layout UVs
Tools
used:
Used
tools in UV editor> first I selected one UV point of the the front and
side wall and then : Select > Select Shell + Move and Scale tools
In
viewport I have selected the points on the inner side of the window
Tools
used:
Just
point selection
At
this stage, since I did the planar UV mapping on walls, the UVs for the windows
are flat and the texture will look like it is stretched when I try to render it.
To
get a better result I decided to scale the inside window UVs like in third picture.
So to scale them I've selected the points in viewport (using vireframe shading
- pic1) and converted selection to UVs (pic2). Then in UV window I scaled the
UVs just like in the third picture.
Yes,
the UVs for the windows are not perfect because when you get close to it it may
be visible that the tex is distorted but since in this scene the windows are far
away from the camera this will work pretty fine.
Then
in UV editor I converted selection to UVs
After
that I've scaled the UVs like in the picture above
Tools
used:
Select
> Convert Selection to UV
Tools
used:
Scale
tool
The
last step to do, after the UV definition, is to make a snapshoot on which I will
paint texture in Photoshop. So, I went to the UV Snapshot option in UV editor
and I've set the resolution (1200x1200), the TGA format of the picture and clicked
OK. After this I got the image with UV snapshot on my disk. Next step: start Photoshop...
The
image with UVs that maya saved to the file, on which I will paint in Photoshop.
