Lecture Autodesk inventor Solid modeling – Primitives and boolean operations

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

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

In AutoCAD, the following dimensions are associated with the three coordinate axes:

Solid Composites

Boolean operations used in solid modeling are: Union

Intersection

Subtraction

Union means set of all elements

belonging to either A or B

Union of two or more solids

creates a composite solid

composed of combined volumes

of these solids

In set theory, the union of two sets, A and B, is represented pictorially as:

Set of all elements belonging

to both A and B

A ∩ B

Intersection of two or more

solids

to original solids

Intersection of two sets, A and B:

Subtraction 1

Set of all elements

belonging to A but not B

A – B

Subtraction of two solids

first solid minus common volume shared with second solid

Subtraction of two sets, A and B:

Subtraction 2

Alternatively, B - A is

represented pictorially as:

Solid Modeling – Primitives and Boolean Operations

Chega!