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Genetica Tutorials
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Using Effect Maps
This tutorial shows you how to generate
various effect maps, such as bump and specular maps, for use in your
external 3D application.
Originally texture artists worked with only a few channels: red, green,
and blue channels were used to specify how much of each color was
present at every pixel, with possibly an alpha channel to dictate how
opaque a given pixel was.
Modern 3D environments give texture artists a slew of additional
material channels to work with. The specular channel, for example,
controls how shiny each pixel is, allowing some parts of a material to
glint as they catch the light, while the bump channel helps give your
materials a three-dimensional appearance. Channels such as these have
allowed texture artists to create materials of unprecedented realism,
but have also required artists to spend more time creating additional
image maps for each texture.
Effect maps are Genetica's answer to the additional channels required by
modern textures. They will not only save you time, but have been
designed to allow maximum flexibility in how they are used.
Unlike traditional color channels,
there is no right or wrong correspondence between effect maps and the
channels they are used in. As shown above, by experimenting with the
numerous effect maps provided by Genetica, you can create materials that
lend significantly different feelings to your final scene. For example,
while Genetica's effect maps have been used to give the material to the
left a bubbly, cobblestone-like appearance that make it more appropriate
for an outdoor environment, the material to the right has been given a
smoother, more polished look that is better suited for indoors.
Meanwhile, effect maps were used with the middle version to fill its
grooves with grime, making it more appropriate for a dungeon
environment.
Step 1
In the Start tab, select the "Tile"
preset category, then click the "Earthy Brown Herringbone" preset
texture.
Let's explore the texture we just opened to better understand the effect
maps that it contains. Because you have just opened this texture, the
Cut & Tile Lab at the very bottom of the texture tree should be
selected--make sure that this is the case. In the panel to the left of
the interface you will find a tab labeled "Effect Maps." Click the
Effect Maps tab to bring it up. You will now see a number of
grayscale images with titles such as "Mortar Height Map" and "Bevel
Height Map."
Because the very root node of the texture is selected, these are the
effect maps that correspond to the entire texture. However, as we
learned from Step 4 of the Genetica Basics
tutorial, we aren't limited to only using the texture as a whole.
Instead, by making use of the Render Branch button, we can render any
portion of the texture that corresponds to the currently selected node.
It therefore wouldn't make sense for the exact same effect maps to exist
at every part of the texture since we would want effect maps that
correspond with the particular part of the texture that we rendered.
For this reason the effect maps appearing in the Effect Maps tab will
change depending on what node is currently selected. Select the
Substance Lab appearing in the main workspace. Your interface should
now resemble the following illustration. Notice how two new effect maps
appear to the left of the workspace that correspond to the currently
selected node.
Step 2
Now we will turn out attention to
rendering the texture and its effect maps for use in our 3D environment.
You will notice that like most textures created in Genetica, the preset
that we just opened has highlights and shadows baked directly into the
texture itself, giving the tiles a three-dimensional appearance.
However, these highlights and shadows may not correspond to the position
of the actual light source in our final scene. We will therefore
activate the Color Only Render button in order to strip away these baked
highlights from the texture, allowing our 3D environment to add its own
highlights as needed. The following image shows how the texture will
look with and without Color Only Render active.
Set the render resolution to 512 x
512 with anti-aliasing disabled. Activate both the Color Only Render and
Render Effect Maps buttons. The render settings portion of the main
toolbar should now resemble the following image. Notice the two
activated buttons on the right.
Click the Render Texture button.
Step 3
After the texture is finished
rendering, Genetica will automatically switch to the Render tab. Due to
the Color Only Render option that was activated before rendering, the
texture should appear flat. Your interface should now resemble the
following illustration.
First we'll save the color only version
of the texture, which should already be selected and visible in the
Render tab. Save the image to your hard drive by either clicking
the Export Image button found on the Render tab's button bar, or by
clicking File > Export Image.
Next we will examine the available effect maps to determine which ones
we want for our final scene. As indicated in the image above, you can
use the dropdown within the Render tab to switch between effect maps.
Which effect maps we choose to use with which material channels in our
3D environment is largely a matter of taste. As indicated by the very
first illustration in this tutorial, a vast range of results are
achievable by using different effect maps in different ways.
For this tutorial we will make use of three of the effect maps, as
described below.
You may have noticed from the previous
illustration that we intend to use both the displacement channel and the
bump channel of our external 3D application. The reason is that
displacement channels excel at defining the overall thickness of a
material since they actually modify the geometry of the shape itself.
Bump channels, on the other hand, are better at creating the very fine
bumps on a materials' surface. But as mentioned throughout this
tutorial, which effect maps you use in which channels depends largely on
taste. If you wanted to do the job using a single channel, for example,
you could try the "Combined Texture" effect map which combines both tiny
details and overall elevations.
Save the "Combined Height Map" effect map by first selecting it
using the effect map dropdown, then by clicking the Export Image button,
both of which are indicated in the image before last. Please note that
if you are working in a real-time game environment, you may need to
convert the image into a normal map by clicking the Make Normal Map
button (also indicated in the image before last) before saving the
image. The Make Normal Map option is available in the Pro edition of
Genetica.
Repeat those steps to save the "Tile and Mortar" effect map and the
"Tile Material" effect map.
Step 4
Create a shader in your external 3D
application. Assign the color only map that you saved to the color
channel of the shader. Assign the "Combined Height Map" effect map to
the displacement channel. Assign the "Tile and Mortar" effect map to the
bump channel. Assign the "Tile Material" effect map to the specular
channel.
Please note that what channels are available to you will depend on your
specific 3D environment. For example, if you are working with a
real-time game engine, you may not have a displacement channel
available, but you may have a parallax shader instead which will serve
the same purpose. Please consult your 3D environment's documentation for
more details.
The following image shows our shader assigned to simple sphere and plane
objects, illuminated by a spotlight.
Now that we have learned how to make
use of effect maps to enhance a material, let's take a closer look at
the first illustration of the tutorial.
You will recognize the first of the
three versions as the material we constructed throughout this tutorial.
The second version of the material is very similar, except the "Combined
Texture" effect map was placed in the material's diffuse channel.
Diffuse channels control how much light reaches various parts of the
material. In this situation it was used to create the impression that
dirt has settled into the deeper cracks of the texture, making it
appropriate for a dungeon environment.
The opposite approach was taken for the third sphere. In this case a
modern, reflective floor was sought after, although the tiles were
desired to be more reflective than the mortar. To achieve this, the
"Combined Texture" effect map was placed in the reflection channel,
illustrating how the same effect map used to make the middle sphere look
older could also be used to make the rightmost sphere look newer. Other
changes included strengthening the specular highlight and removing the
displacement channel to flatten the material.
Next: The Making Website
Thumbnails (Pro) tutorial shows you how to use the Pro edition's
batch processor to quickly turn a number of textures into thumbnails for
display on your website.
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