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Ray Tracing
Ray tracing is a technique for creating realistic looking images by tracing
rays of light as they bounce around a scene. ShaderMaker now has a new
color node called "Raytracer" to give you this ability. Be aware that
using ray tracing can add a significant amount of time to your rendering,
but you may feel that the results are worth it. Ray tracing is primarily
used to simulate reflective or transparent materials, but you can use
it with the Diffuse, Specular or Ambient inputs. In these cases, the ray
that is traced is perpendicular to the surface (the Normal vector).
When a ray of light
enters a transparent material like glass, the light can be bent, or refracted.
The amount of light that is able to pass through the surface is controlled
by the "Refraction" parameter, and the amount by which the light is bent
is proportional to the ratio of the index of refraction of the material
the light is leaving and the material it is entering. (Note that the "Environment"
input has been renamed "Reflection" and the "Refractivity" input has been
renamed "Refraction".) The table below shows the index of refraction of
a few common materials. [Note that these values have been changed in PiXELS3D version 3.5.]
| Material |
Index
of Refraction |
Vacuum
Air
Water
Crown Glass
Dense Flint Glass
|
1.0
1.0003
1.33
1.52
1.66 |
To use Ray tracing:
- Open the "Render
Setup" dialog box.
- Make sure that the "Raytracing" check box is checked. Note that you
must have the Studio or Studio Pro versions of PiXELS3D to use ray tracing.
If you have the Standard version, the Raytracing check box will be disabled.
- Set the "Recursions" parameter. This determines the maximum number
of times a ray is allowed to be reflected or refracted before the final
color is determined. This can be important for example in a hall-of-mirrors
situation, in which your scene has two parallel mirrors. Without a recursion
limit, a ray of light could bounce back and forth forever and your rendering
would never finish.
- Click OK.
- Select an object in your scene.
- Open the Shader Manager window.
- Click on the cell for the shader to which you want to add ray tracing
or click in an empty cell to create a new shader.
- Select Raytracing from the "Reflection" or "Refraction" pop-up menus.
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