Graphics Programs Reference
In-Depth Information
Figure 7.23
The wooden handle
after the texture
has been scaled and
placed
you can use Maya's Interactive Photorealistic Rendering (IPR) to
see your changes in real time. Choose the camera panel to render,
and click the IPR Render the Current Frame button ( ) in the
Status line; or choose Render
➔
IPR Render Current Frame.
The Render View window shows a lower-quality render of the axe. It
prompts you to select a region to begin tuning. Drag a marquee selec-
tion in the Render View window around the handle. IPR refreshes
that part of the window. Every change you make to the texture place-
ment node prompts IPR to update that section of the render, giving
you a fast update on the positioning and scale of the Wood texture.
12. Select the texture placement node, and scale it up in the three axes
until you get a good-looking grain. Figure 7.23 shows a well-spaced
wood grain.
The scene file
axe_texture_B.mb
in the Axe project on the CD will bring you up to
this point.
Figure 7.24
The Layered shader
in the Attribute
Editor
Layered Shaders: The Metal Spike
Currently, the entire length of the handle is shaded as wood, including
the top spike. The spike on the axe head should be metal like the axe head.
You can approach this in two ways: with geometry or with shaders. If
you manipulate the NURBS geometry, you select a horizontal isoparm and
detach the spike portion of the handle to make it a separate surface. You
then assign a Metal shader to the new tip surface.
Using a shader instead of cutting up or creating more geometry can be
desirable in many instances. For example, you may not be able to detach
surfaces like this all the time.
The Layered shader is a normal surface shader that allows you to stack
materials on top of each other to assign to a surface. You control which
layer of material is exposed, and by how much, by assigning transparency
values or textures to each layer. Use a Ramp texture to specify where on
the handle the wood stops and the metal starts.
To create a Layered shader, follow these steps:
1. Select the axe handle, and in the Rendering menu set, choose Lighting/
Shading
➔
Assign New Material
➔
Layered Shader to open the Attribute
Editor, as shown in Figure 7.24. By default, the Layered shader contains
a green layer in the top of the Attribute Editor window. From left to
right, the layers are displayed in the order in which they appear from
top to bottom as they're assigned to the surface. (This means the left-
most shader in the Layered shader is on top of all the others.)
