Lecture Autodesk inventor Parametric sketching

Parametric Sketching


Motivation
Solid primitives not typically supported in
parametric modelers  must create a 2D
profile, then sweep


Feature Creation Procedure
1. Choose sketch plane, either a:




Default work plane
Planar face of existing feature
Work plane

2. Rough sketch


3.
4.
5.
6.

Some geometric constraints applied

Add/delete geometric constraints
Parametric dimensioning

Feature creation
Repeat 1 - 5


Construction Geometry
Geometry created as part of
the parametric modeling
process that does not
represent actual part
geometry. Includes:




Work planes
Work axes
Work points

Construction geometry
appears in feature tree


Default Construction Geometry:
Inventor
Work planes – mutually perpendicular




YZ

XZ
XY

Work Axes




X (red)
Y (green)
Z (blue)

Work Point


Origin of WCS


Rough Sketch
Parametric sketching
imitates actual
sketching process 
rough, approximate


Sketch Plane Views

View normal to
sketch plane

Isometric View


Geometric Constraints
Typical constraints include: vertical,
horizontal, collinear, concentric, tangent, etc.
Inventor constraints


Display Geometric Constraints
Software includes option to show
constraints


Add/Delete Constraints
User can manually (explicitly) add
constraints
tangent

concentric

equal


Parametric Dimensions
Add parametric
dimensions to fully
constrain profile
Each parametric
dimension has two

components:



Numerical value
Name

Fully Constrained Sketch


Parametric Dimensions - 2
Default parameter names (e.g., d0) can be changed
Equations can be used to generate parameter value


Under and Over-constrained Sketches
Vertical position of
hole not specified

Under-constrained

Angle not
necessary

Over-constrained


Parametric Sketching