Models in a CAD system affect drawings, parts, assemblies, and various tables and forms. The best templates look professional, save labor, and reduce errors. Designing templates is an occasionally used skill, sometimes delegated to the intern.
This specialized effort is intense at the start of a project and then becomes a matter of sporadic maintenance. In other words, a learning curve occurs early and is followed by relearning curves.
Sidebar: A specific consumer 3D CAD brand is under discussion. For your information, the Model Wizard add-on for this 3D CAD package is a great tool for designing and administering models. I have no affiliation with this product or any other CAD product, but I had the good fortune and pleasure of being part of an engineering team with its developer.
The Model Wizard addresses the rarely used aspect of model design. The add-in’s learning curve is more about understanding the settings to achieve preferences and less about the syntax of links using custom properties to share product manufacturing information (PMI) between files.
If you administer CAD projects that involve staff turnover and standards, you should at least be aware of the stability and consistency that the Model Wizard provides.
For those interested in designing ad-hoc, nitty gritty DIY models, we now refer to a CAD project from previous episodes. In summary, models from various sources are merged under the support of a new project – the imaginary FMA cart.
Our drawing model has a legacy, not as charming as having a fax number, but close. In the past, before paperless manufacturing became the norm, final designs were always printed and stored in a flat file.
Part of our pattern legacy is 22 x 34 inches. paper corresponding to ANSI C size. Figure 1A gives an idea of the size of the text on the printed sheet. If we wanted a different sheet size, we would start with a different sheet size as a starting point.
From previous episodes we have a good start on a data entry form to collect the PMI. Figure 1B displays the roll of this form in the description path. It starts in the 3D model (the PMI is entered and saved via an input form) and ends in the 2D drawing (text displayed in the title block). All of our PMIs (material, author, etc.) follow a similar link.
With the CAD mark used, when a drawing file is opened, the sheet format of the drawing will be displayed, with the sheet format guiding the retrieval and display of the PMI found in the 3D model. In other words, the drawing is a container for the sheet format (border) and the different views of the model. There are templates for drawings as well as sheet sizes.
Sheet formats are protected against accidental changes. Sheet formats are edited like an ordinary 2D sketch. Completed sheet formats can be exported and can then replace the sheet formats used by existing drawings or drawing models.
Several CAD-oriented policy decisions guide our model design:
- The PMI is stored in component files.
- The drawing file displays (ie automatically fills in the title block) the PMI found in the component file.
- Sheet 1 in the top right will have a revision table with zone coordinates.
- Subsequent sheets will have a dummy revision table that says “SEE SHEET 1”.
- Sheet 1 will contain standard property statements and notes; subsequent sheets will reference sheet 1 whenever possible.
- All sheet title blocks should be legible when printed on 11 x 8.5 inches. paper (B size).
- All sheets should have a perimeter border/area grid with rows AF and columns 1-8.
- Model users are expected to scale component views to fit within the border.
Since the previous episode, updates are planned for default grades and, possibly, default tolerances. We will keep these changes on the to-do list. Setting up the revision table is more fun.
A revision table can have easy-to-add columns, font sets, and widths, and can then be saved as a template. This revision table model can then be inserted into a drawing model.
Revision tables feature labor saving capabilities. One of these capabilities automates data entry of the coordinates of the area on the drawing where revision symbols have been added.
The drawing model we inherited has a difference with the zone settings for the revision table. In Figure 2, the AF column labels are in a blue box. Column labels 1-8 are in an orange box. It is the quantity of labels, not the labels themselves, that is wrong.
In Figure 2, the Sheet Properties dialog box shows the zone settings for the revision table, currently set to four rows and four columns. This is corrected in six rows (AF) and eight columns (1-8).
Auto update area
The epiphane Auto-update zone cells for revision table setting causes the table to automatically update the cells in the zone column based on the locations of the corresponding revision symbols.
In picture 3, the results of adjusting the zone parameters in Figure 2 are displayed. Note that the location of the revision symbol (triangle around B) is in the fifth row (labeled E) and second column (labeled 2) of the sheet. Thus, the E2 area appears for the REV B row of the table.
As can be seen from the model preview in Figure 1A, issues remain with font sizes, ratings, and what is and is not PMI. Who needs a property to customer? Do we not know the name that must appear on the drawing?