Predefined Objects

IVL has predefined atomic types that the programmer may use to create graphical objects. These types represent all the VRML nodes derived from SoShape and exclude those nodes derived from SoVertexShape. IVL types are given the same name as the corresponding VRML node.

• Cone. A unit cone centered at 0,0,0.
• Sphere. A unit sphere centered at 0,0,0.
• Cylinder. A unit cylinder centered at 0,0,0.
• Cube. A unit cube centered at 0,0,0.
• AsciiText. A unit height, zero depth 2D text object whose string field must be set before it can be drawn.

Additional atomic types can be added easily. We have extended the VRML set of primitives to include:

• Pyramid. A unit pyramid centered at 0,0,0.
• Torus. A unit torus centered at 0,0,0. The ratio of diameters must be specified before it can be drawn.
• Text3. A unit height, unit depth 3D text object whose string field must be set before it can be drawn.

IVL also provides ``environment'' nodes in the form of light sources. The light sources can be placed, transformed, and colored in the same manner as shapes.

• DirectionalLight. A light source of parallel rays travelling in the -Z direction.
• PointLight. A light source with rays eminating radially.
• SpotLight. A light source producing a cone of light in the -Z direction.