Chapter 2 Sketching, Constraining & Dimensioning

After completing this chapter, you will be able to –Change the sketch and part options as needed –Sketch an outline of a part –Create geometric constraints –Dimension a sketch –Create dimensions using the automatic dimensioning tool –Change a dimension’s value in a sketch –Import AutoCAD DWG data Chapter 2 - Objectives

Sketch & Part - Application Options Options –Customized your preferences –Settings are global –Affects all open & new Inventor documents

Sketch - Application Options Constraint Placement Priority Display Overconstrained Dimensions Snap to Grid Edit dimensions when created Autoproject edges during curve creation Autoproject edges for sketch creation and edit Autoproject part origin on sketch create 3D Sketch

Part - Application Options Sketch on New Part Creation Construction Auto-hide in-line work features Auto-consume Work Features and Surface features

Part - Application Options 3D Grip Dimensional Constraint Relocation 3D Grip Geometric Constraint Relocation

Units –Default unit of measurement –Part, Assembly & Drawing files –Template file –Changing - Overridden –Edit dimension

Templates –New files created from a template –Add or Modify templates –Template directory –Subdirectory New Tab

Creating a Part From the Open dialog box click the Standard.ipt icon in the Open dialog box From the New file drop list on the Standard toolbar

Creating a Part Sketches & Default Planes –Sketch plane 2D objects are sketched Active sketch Three planes –XY,YZ, and XZ Three Axes –X, Y, and Z Center –Origin - point at the intersection Browser New Sketch –Active sketch

Sketch the Outline of the Part Step 1 - Sketches Overview –Sketching strategies, tools, & techniques Outline Draw to finished size/shape Visual Guide – distance & angle No overlaps & gaps Keep shape simple Closed vs. Open shape –Sketch Tools Sketching tools Expert mode on/off

Sketch the Outline of the Part Using the Sketch Tools –Visual feedback Line Tool –Powerful tool –Endpoint - Arc Inferred Points –Dashed lines –Endpoints horizontal vertical perpendicular

Sketch the Outline of the Part Automatic Constraints –Constraint symbols Scrubbing –different constraint applied –move the cursor so it touches Precise Input –specified length or angle Selecting Objects –individually objects –multiple objects –color change Deleting Objects –right-click

Measure Tools Measure –Distances Points Edges Faces Parts –Angles –Loops –Area

Analysis Tools Measure –Additional Options Click the arrow in the Measure dialog box ResetClears the contents of the measurement box Add to AccumulateAdds the measurement in the measurement box to the accumulate Clear AccumulateClears all measurements from the accumulate sum Display AccumulateDisplays the sum of all measurements added to the accumulate All DecimalsChanges the decimal display between all decimals and the number of decimal places specified in the document settings

Exercise 2-1 Creating A Sketch With Lines Creating a Sketch With Tangencies Exercise 2-2

Constraining the Sketch Step 2 - Geometric Constraints –Apply behavior –Create relationships fully constrain fix constrain –Constraint Types 11 geometric constraints

Constraining the Sketch Geometric Constraints –Adding Constraints Applying Over-constrain Duplicate “Adding this constraint will over-constrain the sketch” –Snap Midpoint, center & intersection Coincident constraint

Constraining the Sketch Geometric Constraints –Dragging a Sketch Constrained or Not Geometry stretches –Showing Constraints To see applied constraints Objects change color –Deleting Constraints Right-click Show all & Hide all

Construction Geometry Standard toolbar Add dimensions and constraints Not visible when a feature is created Always available in the sketch

Exercise 2-3 Adding and Displaying Constraints

Adding Dimensions Step 3 – Adding Dimensions –All dimensions created are parametric –Control & change size of geometry –General Dimensioning Create linear, angle, radial, or diameter Automatically snap Extension lines Preview image –Dimensioning Lines Endpoints - two Length –Dimensioning an Angle Two lines

Adding Dimensions –Dimensioning Arcs and Circles Circumference Arc = radius Circle = diameter –Diametric Dimensions Revolved part Represent a quarter outline Linear diameter Axis of rotation –Dimensioning to a Tangency Arc or circle Constraint symbol changes Two quadrants

Adding Dimensions Entering and Editing a Dimension’s Value –Automatically appear –Change the value –Edit Dimension option –Default value –To change double-click –Enter exact value –Accurate to six decimal places –Smallest dimensions first

Adding Dimensions Entering and Editing a Dimension’s Value –Repositioning a Dimension New location Origin points cannot be moved –Over-Constrained Sketches Inventor will not allow –over-constrain –duplicate constraints –conflict with another constraint –Driven dimension Reference dimension Parentheses Over-constrained dimensions option

Adding Dimensions Auto Dimension –Automatically apply Dimensions Constraints –State number of dimensions or constraints required to fully constrain the sketch –First apply critical constraints and dimensions –Will not override or replace existing constraints or dimensions

Exercise 2-4 Dimensioning A Sketch

Opening/Importing AutoCAD Files Copy to clipboard within AutoCAD and Paste in Inventor Open/Import AutoCAD & AutoCAD Mechanical Files –New Drawing –New Part –Title Block –Border –Symbol –2D and 3D Import 2D geometry to an active sketch (part or drawing)

Importing Other File Types SAT STEP PRO/E up to Version 20 DXF IGES –Construction Environment –Toolset

Exercise 2-5 Inserting an AutoCAD File

Summary ToDo This Modify the Sketch options of Autodesk Inventor Click Tools > Application Options and click on the Sketch tab. Modify the Part options of Autodesk Inventor Click Tools > Application Options and click the Part tab. Create a new part fileClick the New icon in What To Do and then click the Standard.ipt icon on the Default tab, or click Standard (unit).ipt on one of the other tabs. Make a planar face, a work plane, or a nonactive sketch in the active part the active sketch Click the Sketch tool on the standard toolbar and click a face, a work plane, or an existing sketch in the Browser. You can also click a face, a work plane, or an existing sketch in the Browser and then click the Sketch tool from the standard toolbar or press S.

Summary ToDo This Sketch the outline of the partUse the 2D Sketch tools on either the Panel Bar or the Sketch toolbar. Add geometric constraints to a sketch Click a constraint from the constraint pop- up menu on the Sketch Panel Bar or Sketch toolbar, or right-click in the graphics area, select Create Constraint from the menu, and select the specific constraint. Add parametric dimensions to a sketch Click the General Dimension tool on the Sketch toolbar, or right-click in the graphics area and select Create Dimension from the menu or press d. Import AutoCAD dataEither open the file using the Open tool or click the Insert AutoCAD file tool on the 2D Sketch Panel Bar or Drawing Sketch Panel

Project Exercise Chapter 2

Applying Your Skills Skill Exercise 2-1 Skill Exercise 2-2