The Initial Graphics Exchange Specification (IGES) is an American National Standard whose intended purpose is to facilitate transfer of data between CAD programs. ZEMAX currently supports version 5.3 of the IGES standard. For more information on IGES, see Reference 2.

IGES objects are stored in the {zemaxroot}/objects folder, and are imported by the Imported object:


This object is exported from SolidWorks:



Now this object is exported using whatever SolidWorks considers most appropriate, probably NURBS³. It is rendered on-screen using facets, because IGES objects can be extremely complex:



It is important that you understand that ZEMAX uses these facets for only one reason: to draw the object on-screen. IGES objects are represented internally as exact, smooth objects, not as a set of facets like STL objects.

There are a set of properties that you can use to control the Imported object. These controls apply also to STEP and SAT objects:



The properties are:

• Material. Only one material can be applied per object. As this coffee pot consists of a glass jar, plastic lid, plastic handle, aluminum ring to hold the handle onto the jug, and some metal screws that hold the handle onto the ring, these objects should be exported from the CAD package separately, and then imported into ZEMAX individually. Then each sub-object can be given the appropriate optical properties. The use of relative object references allows all sub-objects to be positioned relative to a master object, so that the whole coffee pot can be moved and rotated as a single unit.
• Scale. This is a dimensionless scale factor that allows you to increase or decrease the size of the object
• The Mode flag controls the tradeoff between set-up time and ray tracing speed. Use mode 1 for fast set up time and slower ray tracing, mode 2 for medium set up time and medium ray tracing, and mode 3 for slow set up time and fast ray tracing. Generally use mode 1 during set-up of the system in ZEMAX, and mode 3 for tracing a large number of rays for detailed analysis. Note that accuracy is not affected by the mode flag. Only ray-tracing speed and the initial loading time of the object is affected
• X, Y and Z Voxels define how many volume elements are used to define an invisible bounding box in which the object is defined. Voxel technology allows for fast ray tracing by precomputing which objects, or portions of objects, lie within a given voxel. A ray entering a voxellated space may only intersect some subset of the total number of voxels; and therefore only these voxels need to be checked for possible ray-object intersections. The greater the number of voxels, the longer the set-up time but the faster the ray tracing. It generally takes some experimenting to determine the optimum number of voxels. Note that accuracy is not affected by the number of voxels. Only ray-tracing speed and the amount of memory required to represent the object is affected
• Chord Tolerance affects only the rendering of the solid within the layout plots. To render the solid, ZEMAX converts the solid to list of triangles which approximate the shape. The tolerance is the maximum allowed distance in lens units between a single triangle and the actual surface of the solid. More triangles are added if the tolerance is set smaller which yields more accurate rendering, at the expense of speed and a larger memory requirement. The default value of zero will use a chord tolerance related to the size of the object sufficient to generate a coarse approximation of the object shape that will render quickly. Again, the accuracy of the ray-tracing is not affected by this setting