A shader can be used for multiple objects. A shader named "::defaultShader" is automatically created if necessary and referenced if no shader has been explicitly created. When Cuboids, Cylinders or Ellipsoids are created, the default shader is assigned to them. A new shader may be created with the "Create" button in the Shader/Light view. To assign the shader to the the object, select one or more objects in the orthogonal views, and a shader in the Shader/Light view, and hit the "Assign" button.
Parameters of objects edited by the Shader/Light view may be modified using the optionmenus and entryfields at the bottom of this view. These will be limited as appropriate for that object. For example, the PointLight has no such parameters, the spotlight has sharpness and shadow parameters and the shader has various different parameters according to which type it is.
The color wheel to the right of this view allows the color or colors
to be modified. The color wheel is derived from reference [5] Eff.
Tcl/Tk . For the PointLight, Spotlight and many Shaders, only one color
value is required. Some shaders require two colors; for example the "Wood"
shader. In this case the target color is a parameter selected by an optionmenu
below. When the type of a shader is changed to one requiring more colors,
then the extra colors are initialized to be the same as the last in the
list of existing colors. If however, the shader is changed to one requiring
fewer colors, then the excess colors, though temporarily inaccessible,
will reappear if the type is changed back to a type requiring those extra
colors.