After completing this chapter you will be able to: Understand the terminology used in 3-D modeling, define the most popular types of 3-D modeling systems, apply Boolean operations to 3-D objects, understand the role planning plays in building a constraint-based model.
Solid Modeling – Primitives and Boolean Operations Solid Primitives Primitives are simple solid objects created directly in a CAD system Examples include: box, sphere, cylinder, cone, wedge, torus Model Building in AutoCAD In AutoCAD, the following dimensions are associated with the three coordinate axes: Length in x axis direction Width in y axis direction Height in z axis direction Length, width and height can be positive or negative A positive dimension indicates movement in direction of positive axis A negative dimension indicates movement in opposite, or negative direction Solid Composites Primitives combined using Boolean operations to create solid composites Boolean operations used in solid modeling are: Union Intersection Subtraction Union In set theory, the union of two sets, A and B, is represented pictorially as: Union means set of all elements belonging to either A or B A B Union of two or more solids creates a composite solid composed of combined volumes of these solids Intersection Intersection of two sets, A and B: Set of all elements belonging to both A and B A B Intersection of two or more solids creates a composite solid composed of volume common to original solids Subtraction 1 Subtraction of two sets, A and B: Set of all elements belonging to A but not B A – B Subtraction of two solids creates a composite solid composed of volume of first solid minus common volume shared with second solid Subtraction 2 Alternatively, B A is represented pictorially as: Solid Modeling – Primitives and Boolean Operations Chega! ... movement in opposite, or negative direction Solid Composites Primitives combined using Boolean operations to create solid composites Boolean operations used in solid modeling are: Union Intersection... composed of volume of first solid minus common volume shared with second solid Subtraction 2 Alternatively, B A is represented pictorially as: Solid Modeling – Primitives and Boolean Operations Chega!... composed of volume common to original solids Subtraction 1 Subtraction of two sets, A and B: Set of all elements belonging to A but not B A – B Subtraction of two solids creates a composite solid composed of volume of