tailieunhanh - 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 equal tangent concentric 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 (., d0) can be changed Equations can be used to generate parameter value Under and Over-constrained Sketches Under-constrained Over-constrained Vertical position of hole not specified Angle not necessary Parametric . | 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 equal tangent concentric 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 (., d0) can be changed Equations can be used to generate parameter value Under and Over-constrained Sketches Under-constrained Over-constrained Vertical position of hole not specified Angle not necessary Parametric Sketching