Lecture Autodesk inventor Solid modeling – Primitives and boolean operations

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!