Keeping In Control with Constraints
Scott Onstott · 2017
This chapter guides users on how to create three types of constraints in the AutoCAD® 2018 program, including geometric, dimensional, and user created. Once the design has been sufficiently constrained, users will make a host of geometric and dimensional changes simply by changing a single parameter. Geometric constraints allow users to force specific 2D objects to be coincident, collinear, concentric, parallel, perpendicular, horizontal, vertical, tangent, smooth, and symmetric; to have equal lengths or to be fixed in world space. Parallel, collinear, concentric, and equal constraints always appear in pairs. Multiple constraints are grouped together in what is called a constraint bar. Dimensional constraints allow users to control object sizes with specific numerical values and to set up dynamic dimensional relationships with mathematical equations and formulas. User constraints are not tied to specific geometry but hold values calculated from dimensional constraints.