Importing and Exporting Files

4.Stitching

Stitches together a set of faces to form a single sheet or solid body

5.Geometry Repair

Heals inaccuracies in the geometry

6.Postprocessing

Corrects face normals and removes duplicate vertices and faces no longer associated with the geometry

7.Termination

Removes attributes used in the healing process.

Healing may be done manually or automatically. Manual healing allows you to apply the healing to a specific area of the model and/or change the tolerances used during each phase of the healing. Automatic healing allows the entire process to be performed in one operation. This operation automatically determines the appropriate tolerances to be used in each healing phase, provides statistics on the various healing processes, furnishes results of automatic healing, and gives an analysis of the healed model.

How to Autoheal an Object

1.Select an object or objects.

2.Select Tools|Healing|Autoheal

The TracePro macro output window opens and documents the actions of Autoheal. Autoheal determines what healing processes are necessary and then performs the operations.

How to Manually Heal an Object

1.Select an object or objects

2.Select Tools|Healing|Begin Healing

3.Use Tools|Healing|Analyze to see if your object requires a Simplify, Stitch, or Geometry repair.

4.Use Tools|Healing|Heal to perform the necessary repairs.

5.Select Tools|Healing|End Healing to finalize the repairs.

During the healing process, special Healing properties are added to the objects. The End Healing command returns these properties to their prior settings and removed the extra Healing data.

Reverse Surfaces (and Surface Normal)

When you select Tools|Reverse Surfaces, TracePro reverses the direction of the outward pointing surface normal. Solid objects use the surface normal to define the “outside” of the object. For example, a glass sphere is normally defined with its surface normal pointing away from its center, thus the inside is defined as Glass. If it is defined with its surface normal pointing toward its center, this has the effect of defining all space, except the sphere, as Glass.

This command is often used to correct geometry errors resulting from importing bad geometry from a STEP or IGES file.

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Creating a Solid Model

Combine

When you select Tools|Combine, TracePro combines any pre-selected surfaces into a solid. For example, a cube can be defined by 6 intersecting objects, each with one surface. Or, these can be combined into one object with six surfaces. The Combine option lets you create objects by connecting existing surfaces into a single unit. Remember to select the relevant surfaces before you select

Tools|Combine.

IGES file are often exported as surfaces which can be combined either on import or with Tools|Combine.

Lens Design Files

You can import lens design data into TracePro from popular lens design programs, including ACCOS V, Code V, OSLO, Sigma and ZEMAX. If your installation of TracePro does not include these translators and you need to import files of these types, please upgrade to the latest version of TracePro. You can open the lens design data file as you would any other file, by selecting File|Open. TracePro automatically creates a solid model of the lens design using the curvature, thickness, material, and clear aperture data and saves it as an OML file. During the translation, TracePro converts the lens design materials to the equivalent TracePro materials. If clear aperture data are not present in the lens design file, TracePro may create grossly oversized clear apertures. You will probably find it easier to edit the clear apertures in the lens design program before opening the file in TracePro.

Once the file is imported, you can apply Surface Properties in the usual way, just as if the model had been created in TracePro. TracePro reads and understands the material names in the lens design file and applies the appropriate Material Properties. If some material properties are not applied correctly, you can apply them manually in the usual way. You can check this quickly by using the System Tree and expanding the objects to see the material assigned to them. If an object has a material name but no catalog name, it will not be found when a raytrace is performed. You must look up the material using the drop-down lists in the Apply Properties dialog and apply the correct property.

A file is identified with a lens design program by the extension of the file as shown in Table 2.4. These are the only supported file types for the respective programs.

TABLE 2.4. File Extensions

Extension	Lens Design Program
LEN	ACCOS V LENO file
SEQ	Code V Sequence file
LEN	OSLO file
OSL	OSLO file
LEN	Sigma file
ZMX	ZEMAX file

In the File|Open dialog box, there is a separate choice for each file format, in the List Files of Type: drop-down list at the bottom of the dialog box.

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Importing and Exporting Files

TracePro supports the following features in lens design files (please note that not all lens design programs offer all features):

•Radius or curvature input

•Conic constant (conic surfaces of revolution)

•Aspheric surfaces of revolution (up to r29)

•Global coordinate input

•Specification of material by glass name and manufacturer

•Surface tilts

•Decentered surfaces

•Decenter and return (ACCOS V and Code V)

•Bend optical axis (Code V and OSLO)

•Reverse tilt/decenter (ACCOS V and Code V)

•Circular, elliptical and rectangular clear apertures

•Decentered clear aperture

•Clear aperture rotations

•Circular, elliptical and rectangular obstructions

•Decentered obstruction

•Obstruction rotations

•Surface pickups (radius, thickness, material, aperture, obstruction, aspheric coefficients)

•Dummy surfaces as thin sheet with “No Trace” flag set

•Surface labels and notes

Note: Files containing prisms are difficult for TracePro to import. Most files are imported into TracePro correctly. Prisms are a notable exception. Prisms are often interpreted as plane-parallel pieces of glass.

It is necessary to manually construct the prisms within TracePro. Development of improved methods for importing prisms and other objects is ongoing at Lambda Research.

Merging Files

Often when merging lens design data with data from a CAD program, the coordinate systems do not coincide. The File|Merge dialog box gives you a way to resolve the differences in the coordinate systems by converting one of the files to the coordinate system of the other.

In mechanical CAD programs, it is customary to build models with the x-axis pointing to the right and the y-axis or z-axis pointing up. In most optics programs, including TracePro, the z-axis points to the right and the y-axis points up, leaving the x-axis pointing into the screen.

To use Merge, you must have one of the two models open in a TracePro window. Then you can merge the second file with the open one using Merge.

With one of the models open, select File|Merge to open the Merge dialog. You can manually enter the rotation angles and translation of the second model relative to the first, or you can use default rotation angles. When you press one of

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