Lecture Autodesk inventor: Parametric sketching

Sketching is an important tool for quickly and efficiently communicating design ideas. It is a particularly useful tool early in the design process when several ideas are being explored. A fundamental technique within most parametric modeling programs is to sketch 2-D features then use a 3-D construction operation, such as extrude, revolve, or sweep, to create a 3-D model.

Parametric Sketching     Motivation Solid primitives not typically supported in  parametric modelers  must create a 2D  profile, then sweep     Feature Creation Procedure Choose sketch plane, either a:    Default work plane Planar face of existing feature Work plane Rough sketch    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 Over­constrained  Sketches Vertical position of  hole not specified Under­constrained     Angle  not  necessary Over­constrained Parametric Sketching     ... 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...    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 ... 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