CHAPTER 2	Creating a Solid Model

Introduction to Solid Modeling

Solid modeling is a technique for constructing computer models using “solid” pieces of virtual material, just as you build real hardware out of real material. In a solid model, objects are three dimensional entities defined to be bounded by surfaces. By using solid modeling, you inherently obtain a consistency of modeling that avoids many modeling errors. You can be confident that you are modeling something that is physically realizable.

There are many ways to define and manipulate objects in solid modeling; it is a field in its own right. TracePro offers several ways to create and manipulate solid objects:

•Import data from a solid modeling program,

•Import data from a lens design program - TracePro creates a solid model automatically,

•Create primitive solid objects including blocks, cylinders and cones, spheres, tori, and thin sheets,

•Create solid objects needed for optomechanical systems including optical elements, reflectors and concentrators, Fresnel lenses, tubes, and baffle vanes,

•Create complex solid objects from primitive solids using Boolean operators: Intersect, Subtract, and Unite, and

•Modify solid objects by using the Sweep and Revolve commands.

Model Units

TracePro Models may be constructed and viewed in several units of measure. The dialogs described in this chapter and throughout the manual refer to Model Units. The Model Units are set as a preference and stored with the Model data in the TracePro OML file. See “General” on page 2.48.

Internally TracePro stores geometry data and performs calculations in units of millimeters (mm). The Model Units are used to scale dialog inputs and display outputs from millimeters to the desired dimensional units.

Position and Rotation

Many of the dialogs provide options for position and rotation. During construction TracePro will build the object at the global origin and change the orientation (position and rotation) based on the input data. An object’s position is set by the object’s Working Coordinate System (WCS) from the global origin. TracePro provides an option to display the object’s WCS which may be centered or coincident with a surface vertex. See “Display Object WCS” on page 2.46. Rotation is performed relative to the object WCS using Euler Angles. This is similar to rotating surfaces in lens design programs. The rotations are performed first about the x-axis, then about the y-axis and then about the z-axis. The resulting orientation is not necessarily unique. For instance rotating an object by 90 degrees about the x-axis and then the z-axis will be the same as rotating the