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 2D features then use a 3D construction operation, such as extrude, revolve, or sweep, to create a 3D 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 - 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 - 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 ... 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. .. concentric equal Parametric Dimensions Add parametric dimensions to fully constrain profile Each parametric dimension has two components:   Numerical value Name Fully Constrained Sketch Parametric. .. constraints applied Add/delete geometric constraints Parametric dimensioning Feature creation Repeat - Construction Geometry Geometry created as part of the parametric modeling process that does not represent