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Solid Edge  Modeling Philosophy
❖
Learning Objectives
✴
What is a solid modeling package (Solid Edge, SolidWorks) really?
✴
How are things organized within a solid modeling package?
✴
Are there general guidelines for building robust models?
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❖
Solid modeling software
✴
Solid modeling software appears to be graphics software.
✴
It is really data base software that manages graphic elements.
‣
Each element in the database has certain characteristics that define the
element
•
A line has

a start point

an end point

an equation that locates all points between the start and end points
•
A circle has

a center

a radius

an equation that locates all points on the circumference
✴
To display a graphic element, the software simply displays the
solution to the equation for each element in the data base.
‣
Geometrical relationships apply constraints to the solutions so that the
solution of one equation is related to the solution of another.
‣
Dimensions are another type of constraint linking the solutions to the
equations.
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Solid Edge  Modeling Philosophy
❖
Solid model hierarchy
✴
Sketch primitive
‣
A graphical entity (a
point
,
line
,
arc
,
circle
,
ellipse
,
curve
, etc.) in a
sketch.
•
A sketch primitive is described internally by the equation appropriate to the
shape.

e.g., the equation of a straight line, circle, etc.
•
Sketch primitives are constrained by their

shape (or the equation that represents the shape)

size

size may be determined by
dimensions
and/or
geometrical relationships

geometrical relationships to other entities
•
An
unconstrained
entity is one for which there are neither dimensions nor
geometrical relationships that position and size the entity relative to either
other entities or the global coordinate system.
•
A
fully constrained
entity is one for which the combination of applied
dimensions and geometrical relationships completely locate and size the
entity.
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❖
Solid model hierarchy (cont.)
✴
A
sketch
is a set of sketch primitives (points, lines, arcs, circles,
ellipses, curves, etc.) which are all placed on a common plane
‣
Sketch primitives (entities) are defined by their
•
shape
•
geometrical relationships to other entities
•
dimensions
‣
An entity with neither dimensions nor geometrical relations to other
entities is unconstrained
✴
A
fully constrained sketch
is a sketch in which all the entities are
completely constrained (located and sized) by the set of shapes,
geometrical relationships, and dimensions placed on the sketch
✴
A
profile
is a sketch used to create a feature
‣
Profiles are planar
‣
The profile shows the feature in crosssection
‣
Nonconstruction lines in the sketch represent the projection of feature
surfaces onto the crosssectional plane.
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This note was uploaded on 04/28/2008 for the course AME 308 taught by Professor Shiflett during the Spring '07 term at USC.
 Spring '07
 Shiflett

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