Introduction
to Gradient Ramp maps, 3D maps and blend materials
by Montree T. (easyyong@hotmail.com) - Smoke3dStudio

Gradient ramp
The Gradient
Ramp is a 2D map similar to the Gradient map, however, the Gradient
ramp can be shaded more than 3 and there are several different
types
of
effects that this map can produce
. The Gradient ramp can produce unbelivable effects when
it is mixed with ifself and other maps. It's also easier to use
gradient ramp tiling instead of using 2d maps.
There
is not much explanation required for Gradient ramps, so just take
a look at the example pictures below.
Gradient
ramp: linear type
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| Single Linear |
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Tiling Linear |

Example picture of a linear ramp type: This louvre example uses
a linear gradient ramp on the diffuse and bump map channels.
Gradient ramp: box type
Example
picture of the box type: assigned to bump and diffuse map channels
Gradient
ramp: radial type
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| Single
Radial |
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Tiling
Radial |
Example
picture of the radial type: used as an opacity map
Gradient
ramp: sweep type
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| Single
Sweep |
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Tiling
Sweep |
Example
picture of the sweep type: using sweep gradient ramp on the specular
level map
Gradient
ramp: Mapped type
The Mapped
type is used for adding colors (or sub-maps) on a black and white
map. The different values on a black and white map are replaced
with the color on the gradient bar as the end result.

Example
picture of mapped type masked by a black and white brick map. The
shades of black are replaced with blue on the bar and the white
is replaced with orange.

The end result of the gradient ramp: mapped type
Example of mapped type, colorful mosaic tile
Tips: Basically, I use gradient ramp as a mask map for a 2d mix map
or blend material. It's an easier way to change the color of a map
by using gradient ramp under a mix map rather than putting the color
in gradient ramp itself (unless you have more than 2 color in your
map).
Change
the colors in the gradient ramp map itself.

Change the colors under mix map is easier
3D maps
Noise,
dent, celular, specle, splatter and etc. I will skip defining
these 3D maps as I assume that you have had some basic experience
with them already. We simply use a single 3D map as a bump
map, diffuse map etc.
The effect of a material
that
has more
than two of these 3D maps with itself or other 2d map ie. gradient
ramp, mixed together looks much better.
The
example above shows a stone wall done with pure 3d cellular maps
in several layers assigned to the diffuse, specular and bump
maps. The rest of the materials on other objects are done
with gradient
ramp with 3D maps.
Another
example with all materials created without any bitmaps.
The rice is a cellular map and the meat is gradient
ramp, and the plate uses noise and cellular maps.
Blend material
The
Blend material is a mix of two independent materials with different
shaders (can also be the same). The border of the two materials
are specified by a black and white map that we call a "mask
map".
The first material in the blend slot refesr to the black color
in the mask map and the second
material refers to white. Both materials are overlaid in an area
of the mask map which contains grey. I have a few examples which
are practical to architectural rendering.
Example 1 : Creating a grid ceiling with a blend material.
From
the picture, the material is composed of a grid area and diffuse
light (fluorescent) which are specified by a mask
map.
1.
Mask map
I
use a gradient ramp in black and white shade and a gradient type
of box with 1x1 mirror tiling. The black in the mask map
refers to grid
ceiling area which is material 1 and the white is fluorescent area
(material 2).

This is how the mask map look like.
2.
Material 1

Material 1 (grid ceiling)
Go into material 1, which is thegrid ceiling. I use gradient ramp
with box type again as a diffuse and bump map.

We also need to adjust the tiling of
the grid which is now 3x3 mirror tiling to match with the mask
map (1x1 mirror).

If the tiling numbers
are diffirent from this sample, when you create a material
on your own, the
offset distance
may also be changed to match with the tiling as well.
The
example below shows a mismatched position of thetiling ,caused by the wrong
adjustment on offset distance

3. Material 2

Material 2, fluorescent
Material 2 is fluorescent that is easy to create.
I just change its self illumination parameter to 100 or color it
white. If
you want more detail on this fluorescent, you may add a gradient
ramp map as its self illumination map.

I use 2 layers of gradient ramp to create this
self illumination effect.

Grid Ceiling Chart

The ceiling in the image below is done with a blend
material.
Example 2: Wet floor
Now
that we have covered the blend material and using 2d gradient
ramps, I hope you understand how to use them in your projects.
The following example
is for using 3d maps for a blend material that mostly needs no
UVW map.
First, let me explain more about the legend of
this material and its maps before we go onto the material chart.
The
wet floor consists of 3 materials, mixed together which are:
1. Dry floor
Assign
a 3d noise map to the the diffuse and bump channels. The shader
is an Oren-Nayar-blinn type as I want the floor have roughness.

2. Damp floor
I
just copy the dry material, but change specular level to be brighter,
more glossy and make the diffuse color a bit darker
as the damp floor contains a bit of water that makes its color
darker. I then put in a little raytrace reflection.

3. Wet floor
This
is
the floor underneath the water. I still use the same material
but change the specular and glossiness to be more glossy
than the
water. Remove Bump and add more reflection.

4. Mask map
As
there are 3 basic materials (dry, damp and wet) there will
be one more blend material that is overlayed on another blend material.
I use 2 different dent maps (also 3d map) to specifiy the area
of each material.
Mask 1
Mask 2
Below
are 3d iamges,wet floor, using blend material
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