********** README FILE FOR THE MACRO, 'FLAT_PATTERN' ************ Written by Darren C. Haverstick Paul Mueller Company Springfield, MO Phone: 800-683-5537 Ext 725 Email: dhaverst@mail.orion.org This macro creates flat patterns that result from the intersection of a fitting of some particular cross-section and a cylindrical shell. It also will create a pattern for a repad to go around the fitting at the point of intersection. A repad is simply a band of material welded onto the shell to reinforce the fitting/shell intersection. My company makes a variety of products out of plate and coil steel. Often times, we have a fitting intersecting a cylindrical shell and we need to precisely cut the hole in the shell that the fitting will go into. We do this by making a flat pattern of the 3D surface of intersection, place it on the shell, and cut around it. We also make a pattern to wrap around the outside of the fitting so it can be cut to accurately fit the shell. While creating these flat patterns might be easy in a 3D graphics package, doing it in ME10 is tricky. This macro uses rotational matrices and a descriptive geometry technique to get the job done. You are given a choice of five cross-section types for your fittings: 1) Circular 2) Elliptical 3) Oval 4) Rectangular with Square Corners 5) Rectangular with Rounded Corners. By answering a series of questions, you will tell the macro how your fitting is positioned in 3-dimensional space with respect to cylindrical shell. Several graphics are generated to clarify the questions and aid you in answering them. Once all the questions are answered, the macro calculates points along the perimeter of the cross-section you chose and places them in 3D space. These perimeter points are then projected through the cylindrical shell and the points of intersection a determined. The points of intersection define the boundary of the 3-dimensional surface of intersection. Using a descriptive geometry technique found in any drafing book, the macro takes the 3D points, determines the relationships between them, and 'flattens' them out in to 2D space. The result is a flat pattern of the surface of intersection. The macro can take this process a step further by using the same 3D boundary points to create a pattern to wrap around the fitting itself. The fitting can then be cut by this pattern so that it fits snugly against the shell.