The Direct3D rendering is mostly aimed to imitate details of the
mesh by means of textures insted increasing the polygon count.
The details of the mesh can be drawen on the textures and
mapped onto the faces. Look at the following textured Z Letter where
I've use first texture that found:
Mapping is assigning of texture coordinates to the faces.
Each face has three planar coordinates (U,V) on the texture
plane: each vertex of face has its' own coordinate on texture.
The triangle you get on texture plane with this three UV points
defines a triangular area on the texture that will be fitted into the
face.
On the image above I've drawed additional
lines that shows correlation of original vertices and their UV vertices. Look
attentively to the lower triangle, it's map and result. It's obviouse how triangle
on UV map was fitted into result triangle.
You can also map these UV points into line or into single point,
the last situation paints the face into the color of this point.
To let you create custom materials there is material editor in
ZModeler, where you can operate with existen materials or create new
materials.
To open material editor hit E key or press the material editor
button in toolbar. You will see dialog box of Material editor:
Here there are some areas that I've bounded and enumerated:
1) Selector of material with Delete and Add buttons
that deletes and copies current material accordingly.
2) Materials' parameters: Color, shininess and opacity.
3) The shaded Sample (as a result material)
4) Alpha parameters.
5) Textures block: Material can also be untextured (The one on the shot isn't textured)
There is nothing hard in first and second groups but opacity. Opacity stands for
non-transparencity of material, that means the less opacity the more transparent materials is.
Alpha block controls a kind and parameters of transparencity. By default the most
materials are non-transparent and alpha chanell is unused. To enable transparencity
you need:
Enable Alpha Blending and/or Alpha Test in 3D configuration menu.
Change Alpha chanel type to according.
There are four types: Unused, Blend and Test. The first
ignores alpha and no transparency is avail. The second uses alpha chanel for determining
the level of transparency according to source and destination blend types. Where source
is materials and destination is somthing behind the faces (background color in the upper preview
window). For example, default blending types (Src. alpha for source and Inv. Src. Alpha) means
that only textures' aplha controls trasnparencity: the lighter the aplha component - the less
the material is transparent; the darker alpha component - the more it transparent. You can
make some tests on types of blending. The following example illustrates Blend transparencity:
Test type of alpha transparency works other way:
it ignores the pixels of texture that match the compare function and Reference. For example,
compare funcion >= and reference vaule is 50%, thus all the pixels whose alpha
component is greater or equall then 50% (of maximum) will be displayed. The following example
illustrates Alpha-Test transparencity on the previouse textures and it's alpha using
">=" compare function and "50%" reference value:
The fifth, Textures block describes appearing of textures on
the material. Checkmark primary texture and hit Load button lo select texture. Then you can
customize Blending type.
NOTE: All the blending types takes effect in ZModeler and has no
meaning while saving/exporting. I also STRONGLY RECOMMEND do not use any of specified by default
blending types, since it might crash the program. The defaults are Src. Alpha for source alpha,
Inv. Src. Alpha for destination alpha, MODULATE primary texture and ADD for
reflection map.
Materials are assigned to the faces, using special dialog box.
First of all you need to select some faces you want a material
to be assigned to. Then you press CTRL-A to activate Attributes
dialog box:
Well, this is an Attributes dialog, that will be fully described in
the Attributes topic. As for now all we need is
Material dropdown. You can simply change the selection in this
box and hit OK to assign new material:
Of cause, the material you are assigning must be created first in the
material editor.
This topic covers UVMapping functions. All these functions
are in the Surface.../Mapping... subbranch in the menubar:
Assign UV - Assigns the mapping to the face. Actually, it creates
an object that is displayed in UVMapper only. By editing this object you
edit the mapping.
First you selects a group of facesa and assigns the material to that
group faces.
Second, you activates Assign tool and click on selected faces ("SEL"
button is down). The mappin gobject will be created automatically.
Third, you switch any view to UVMapping view by right-clicking on the
rectangle in the upper-left corner of that view. you will see that object in
the view.
Notice that if there were no mapping assigned to any of faces than these
mapping will be assigned and according UV map will look like source face
on the view you have clicked:
Then you edit this object using standart edit tools with (I recommend)
MUL button pressed down. At the same time you can see the results
in 3D View. Then you switch UVMapping view back.
The other thing you have to notice is that Assign prompts to Hold
SHIFT for FACE-MAP. The Face map is special map when all faces that have
been assigned that way retrieves the same mapping:
Reset UV - Resets UV mapping to the face (or to the selected faces).
Thus, after pressing Assign UV you can assign completly new mapping
Flip UV and Rotate UV - Are reserved.
Note that in UVMapper view there is a TEXTURE. Also in this view each
face use its' own vertices and there is no common vertices for any face.
After you click Assign UV you will see practically the same faces in the
UV view, and this faces represents UV map. Well, the most interesting
thing is that in this view you can edit the mesh (of UV map) like in
other view. Thus you can adjust the mapping. Also I recommend to use
MultyMode when you move vertices in this view.
The normals are used to imitate a smooth surface while real
mesh is not too smooth because of low polygon count. Each vertex has
a normal and thus for editing normals you should switch to vertices level
or stay on objects level (to edit all objects' normals at one time).
All the normals edit functions are in the Surface.../Normals...
subbranch. Here the full description:
Normalize - Normalizes the length of normal vector to 1.0.
Rotation - Rotates the normal. Similar to standart Rotate
modificator, but it rotates only normals.
Scaleing - Scales the length of the normal. The most effective
on shading.
Flip - Flips the normal (changes the direction)
Calculate - Recalculates the normals.
Projection - Progressive method for normals tuning. It projects the
normals outfrom the axis center. If you will hold down the SHIFT key
while pressing the left mouse button, then the normals will be 3D projected.
Look at the fllowing image:
I've also drawed the red lines - the direction of projection. This
method has also parallel projoction by means of holding the CTRL key. The
parallel projection uses the same direction for all normals that you
project. This direction calculated as the middle between all directions
while projecting in normal mode.
By Gismo - The most advanced (for now) method of generating normals.
This method uses vertices of the object named Gismo as centers of projection
method. For each vertex on the mesh it finds the nearest vertex on the
gismo and uses this vertex as the center of projection. This method also
can project in 3D space if you hold down the SHIFT key before pressing the
left mouse button. Note that the more detailed the gismo object the more
smooth the reslut of projection you will get. To select the gismo object you
can simply Hold down the CTRL key and Click on the object. Compare the results
of projectin and Gismo-projection:
The Gismo-projection is very good when you are going to generate normals
for the crome (reflection map) while standart calculation is good when you
are going to generate normals for the good shading.
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