The Plot Thickens Peter K. Sheerin Industry Watch Intergrating CAD, FM and GIS into the Supply Chain Arnie Williams First Draft John Wilson Parametric Glue Figure 1. When the features of a Mechanical Desktop 3D model are correctly constrained, design changes are easy to make. Mechanical Desktop assigns a number to each object in a sketch and uses symbols to indicate each object's constraints. In this profile sketch, object number 0 has two constraints. The symbol L1 indicates it is constrained to be perpendicular to object number 1, and the symbol P3 indicates it is parallel with object number 3.
Constraints can exist between sketch objects and the edges of an existing solid feature.
In fact, such constraints are necessary to fully constrain profile sketches of dependent features. Drafting skills are not nearly as important in creating parametric solid models with programs such as Autodesk's Mechanical Desktop as they are in creating 2D drawings. One reason for this is that it is not necessary to precisely draw objects in their exact sizes in Mechanical Desktop, and sometimes it is not even desirable. Another reason is that Mechanical Desktop does much of the drafting work for you. Even some very complex objects such as helix-shaped springs and threads are created primarily through data you enter in a dialog box.