3.6.2 The Materials Panel ¶
The Materials panel controls material properties of surfaces. It works with the target object in the same way that the Appearance panel does.
Figure 3.7: The Materials Panel.
- Translucent
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This button determines whether translucency is enabled. Geomview supports three different flavours of translucency:
- Alpha-blending with BSP-tree depth-sorting
This is the most accurate flavour for online viewing, but consumes vast amounts of computation time and memory. In this mode single translucent objects are displayed correctly with respect to themselves; however multiple translucent objects may appear in the wrong order on the screen. The notion object means here: top-level geometries as displayed in the geometry target browser.
- Screen Door Translucency
If the machine support OpenGL then there is support for kind-of translucency by masking out (completely) transparent pixels by means of a stipple mask. This is currently very experimental, and the result is somewhat ugly, but fast.
- Alphe-blending without depth-sorting
This is the old naive way of doing quick and dirty translucency. It is fast, but the results are completely incorrect.
When transparency is enabled, a RenderMan snapshot will contain the alpha information, a RenderMan compliant renderer can then generate high-quality pictures, including correct translucency.
- Alpha
This slider determines the opacity/transparency when transparency is enabled. 0 means totally transparent, 1 means totally opaque.
- Diffuse Reflectance
This slider controls the diffuse reflectance of a surface. This has to do with how much the surface scatters light that it reflects.
- Shininess
This slider controls how shiny a surface is. This determines the size of specular highlights on the surface. Lower values give the surface a duller appearance.
- Ambient Reflectance
This slider controls how much of the ambient light a surface reflects.
- Specular Reflectance
This slider controls the specular reflectance of a surface. This has to do with how directly the surface reflects light rays. Higher values give brighter specular highlights.
- Done
This button dismisses the Materials panel.