This article describes the process of using OpticsBuilder to automate the creation of lens drawings by creating a custom drawing template in Creo Parametric. OpticsBuilder can create automated ISO 10110 compliant drawings of circular lenses with the Generate Lens Drawing tool. This tool generates a drawing for a lens with dimensions and material data filled out using custom properties imported with the ZBD file format. The drawing tool executes a macro that handles number formatting, picture and table placement, lens dimensioning, and auto-population of lens data.  

Authored By Jacob Hart

Introduction

Creo Parametric assembly files created using OpticsBuilder contain mechanical and optical components. OpticsBuilder can create drawings of circular lenses using the Generate Lens Drawing tool. The drawing template is the framework that organizes and presents lens geometry and properties in a drawing. This article is a step-by-step guide to understand what information is contained in a custom drawing template and how to create a custom drawing template for use with OpticsBuilder.

Using the OpticsBuilder drawing tool

To use the drawing tool:

1. Import a ZBD file into OpticsBuilder
2. Click Generate Lens Drawing
3. Select the optical component(s) to generate drawings for in the Generate Lens Drawing dialog box
4. Select a drawing template (OpticsBuilder or Custom)
5. Click OK to start the drawing tool

OpticsBuilder drawing template

After the drawing tool is started drawings are created of lens front and cross-section views. Dimensions are added for lens thickness and face diameters. If the user selects the OpticsBuilder template in the drawing tool the drawing will appear as shown below.

When using the OpticsBuilder template the following data is automatically populated in the drawing table if it exists in the ZBD file:

• Lens radius of curvature with sign to indicate concave or convex (R)
• Clear aperture radii (Ø_e)
• Lens material (Glass:)
• Refractive index with uncertainty (N_d)
• Abbe number with uncertainty (V_d)
• Power Irregularity (3/)
• Tilt (4/)
• Surface Imperfection Tolerance (5/)
• Reference wavelength (6/)
• Material Imperfections – Stress birefringence (0/)
• Material Imperfections – Bubbles and Inclusions (1/)
• Material Imperfections – Inhomogeneity and Striae (2/)
• Lens name (Part/DRAWING)
• Drawing sheet scale (SCALE)

Doublets and even aspherical lenses

Doublet lens assemblies automatically generate drawings for individual lenses and the cemented lens group. Aspherical lenses (even aspheres only) have additional drawing sheets generated to include aspheric coefficients and sag tables.

Creating a custom drawing template

The custom drawing template allows a user to define their own drawing template to fit their needs. Users may create tables, notes, pictures, and add parameters related to lens geometry and material properties. If the custom template will have a different drawing size or orientation from the OpticsBuilder template then a new drawing format must be created.

The first step to create a custom drawing template is to create a new drawing format in Creo to select a sheet size and orientation. The Creo drawing format contains the framework of tables, annotations, and graphics that will be a permanent part of the Creo drawing template.

After naming your drawing format click OK to select sheet size, and orientation.

Click OK to create the drawing format. A blank drawing is created with border lines to start the format.

Drawing border creation

The drawing border acts as a reference to create table geometry. To create the border use the Offset Edge tool under the Sketch tab using these steps:

1. Open your empty drawing format
2. Select the Sketch tab
3. Select the Offset Edge tool
4. Select a border edge to offset it a specified distance. To reverse the direction of offset use a negative offset number.
5. Use the Corner tool and hold down Control to select and trim border lines at their intersection

Creating a table

After creating a drawing border you should start creating the drawing table. Tables may be created by either using the Table tool under the Sketch tab, or by drawing sketch lines to create the table cells. This tutorial uses sketch lines to create a table. This gives more flexibility when selecting styles and formats to apply to individual lines in a table.

To start the table you should first select the Sketch tab. In the Sketch tab the line tool can be used to construct a table. Line appearance may be modified by clicking Line Style in the Sketch tab. Lines created with the line tool may be drawn anywhere on a sheet. When creating a sketch entity you will be prompted for snapping references. Any objects chosen  as snap references will automatically be snapped to when the cursor is nearby. Intersections between snapping references and other lines in the drawing format are automatically snapped to as well. 

The Offset Edge tool is also useful for creating tables using lines by creating new lines at a different distances from a parent line in vertical and horizontal directions.

After creating the table, static plain text annotations that will permanently be part of the drawing table may be added to the drawing format. To do this go to Annotate...Note and place the note in the appropriate location in the table. Once the table lines and text annotations are finished you are ready to save the drawing format and start drawing template generation. Save the drawing format as a .frm file using File...Save before moving on to the next steps.

1. Close the drawing format
2. Create a new drawing
3. Select the Empty with Format option
4. Use Browse to load the new drawing format you created as part of the drawing
5. Select OK to start the drawing
6. Select the Tools tab 
7. Select the Template icon to switch to Template mode from Drawing mode

Drawing annotations and custom parameters

Adding annotations is the next step in drawing template creation. Annotations may contain text, lens data contained in parameters, or a combination of text and data. Custom parameters are attached to each lens after ZBD file creation in OpticStudio.

To view custom parameters associated with an optical object during ZBD creation go to Tools...Parameters.

When creating a custom drawing template from scratch there are no custom parameters defined.  However, custom parameters may be called out to populate a table in future drawings by creating a note containing the parameter name with an & preceding it. When a drawing is generated any annotations calling out custom parameters will be populated if the parameters exist.

Text and custom parameters may be combined in a single annotation by adding a parameter, text, and then another parameter name. Both parameter names must be preceded by an &. This is useful for creating data fields that include tolerances. 

The custom drawing template should now be ready to add custom parameter manufacturing data. To aid in drawing creation, custom parameter names used in the OpticsBuilder drawing template for Creo are shown below.

Aspheres

Aspherical lenses are a special case for the drawing tool, with support for even aspheres only. When a drawing is made of an even asphere the OpticsBuilder template includes a sag equation at the top of the first sheet and two additional sheets containing aspherical coefficients and a sag table for both faces of the asphere.

To create the extra sheets for an asphere in a custom drawing template you should:

1. Open your template
2. Add two extra sheets using New Sheet in the Layout tab
3. Add a table using Table in the Table tab
4. Add another extra sheet using New Sheet in the Layout tab
5. Add two more tables using Table in the Table tab
6. Right click each new sheet label at the screen bottom
7. Select Setup
8. Change the sheet format to the correct drawing size and select OK to make a blank sheet
9. Populate the three new tables with aspheric coefficient and sag value parameter names preceded by &
10. Save your template

Saving the drawing template

Once a drawing template is created with a table(s), annotations, and custom parameters the user should save their template as a .drw file using File...Save As...Save a Copy. The sheet format contains the drawing orientation, size, border, tables, and static annotations created. The drawing template contains all dynamic annotations, model views, parameters, and dimensions used. A drawing template references a sheet format(s) when it is saved.

KA-01959