After completing this chapter you will be able to Understand the terminology used in 3D modeling, define the most popular types of 3D modeling systems, apply Boolean operations to 3D objects, understand the role planning plays in building a constraintbased 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 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 Alternatively, B - A is represented pictorially as: Solid Modeling – Primitives and Boolean Operations Chega! ... 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... solid minus common volume shared with second solid Subtraction Alternatively, B - A is represented pictorially as: Solid Modeling – Primitives and Boolean Operations Chega! ... original solids Subtraction 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