1. Chapter 2 Sketching, Constraining & Dimensioning

2. Chapter 2 - Objectives
After completing this chapter, you will be able to do the following:
Change the part and sketch options as needed
Sketch an outline of a part
Create geometric constraints
Use construction geometry to help constrain sketches
Dimension a sketch
Create dimensions using the automatic dimensioning command
Change a dimension’s value in a sketch
Open and insert AutoCAD DWG data

3. Sketch & Part - Application Options
Customized your preferences
Settings are global
Affects all open & new Inventor documents
TRAINER NOTE
Emphasize that settings on tabs of the Application Options dialog box affect all documents.

4. Part - Application Options
Sketch on new part creation
Construction
Auto-hide in-line work features
Auto-consume work features and surface features
3D grips
Edit Base Solids Using
TECHNICAL NOTES
The part tab sets:
preferences for the default sketch plane in a new part file
orientation of the sketch view
behavior of in-line work features after they are used by another work feature
the appearance of construction surfaces,

5. Sketch - Application Options
2D Sketch
Display
Overconstrained dimensions
Spline fit method
Heads-Up Display
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
Point alignment
3D Sketch
TECHNICAL INFORMATION
Snap to grid: Select this option to sketch geometry by snapping to the grid. Clear this selection to sketch shapes freely without regard to size, and later add and edit dimensions to resize geometry.
Autoproject edges during curve creation: Selects existing geometry and projects it into the current sketch by “rubbing” the lines. Projected geometry is reference geometry and cannot be edited.
Automatic reference edges for new sketch: Projects the edges of the selected face into a new sketch. If you do not intend to use the face edges, you may wish to turn this option off to avoid creating unneeded geometry.
Edit dimension when created: Opens the edit dimension box when you place a dimension. Used together with free sketching (grid snap off), this option lets you add precision while still sketching quickly. Clear this check box to place a dimension without editing. Double-click the dimension value to change it later.

6. Units Units Default unit of measurement Part, Assembly & Drawing files
Template file
Changing - Overridden
Edit dimension
TECHNICAL NOTES
Options on the Document Settings tabs affect only the current document.
The Units tab:
Specifies length, angle, time, and mass units.
Specifies precision decimal places for linear and angular dimension displays, and the dimension style.

7. Templates Templates New files created from a template
Add or Modify templates
Template directory
Subdirectory
New Tab
TECHNICAL NOTES
Create templates with your preferred application and document settings so you don’t have to set them every time. Files stored in the template directory are automatically templates.

8. 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

9. Creating a Part Sketches & Default Planes New Sketch 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
Create 2D Sketch
TECHNICAL NOTES
Settings specified on the application options and document settings dialog boxes determine orientation of the sketch objects and default sketch plane.

10. 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
TECHNICAL NOTES
Two ways to sketch in Inventor:
Use grid snap and coordinates displayed at lower right corner of the graphics window to sketch to precise size.
Turn off grid snap and sketch freely without regard to size, then add dimensions later to specify precise size.

11. Dynamic Input Polar or Cartesian Coordinates Persistent Dimensions
Heads-Up Display Settings
Dimension Input

12. Sketch the Outline of the Part
Using the Sketch Tools
Visual feedback
Dynamic Input
Line Tool
Powerful tool
Endpoint - Arc
Object Tracking - Inferred Points
Dashed lines
Endpoints
horizontal
vertical
perpendicular

13. Sketch the Outline of the Part
Automatic Constraints
Constraint symbols
Scrubbing
different constraint applied
move the cursor so it touches
TECHNICAL NOTES
Scrubbing: Brush the cursor along the line or curve you want to constrain to, then move the cursor into the approximate desired position. In cases where more than one constraint is possible, this technique overrides a default constraint in favor of the constraint you selected.
Precise input: enter exact coordinates for sketch geometry as you sketch.
Selecting geometry:
Click and drag left to right to select all geometry completely enclosed in the selection window.
Click and drag right to left to select geometry enclosed and intersected by the selection window.

14. Constraint Persistence & Inference
Turns sketch constraints on/off
When on, sketch constraints are applied while sketching
When off, the constraint icon will appear on the screen, but it will not be applied to the sketch
Inference
Turns the preview of the constraint on/off
When off, Constraint Persistence is also turned off
When off, sketch constraints are not applied

15. Constraint Options
With Constraint Inference on you can control which sketch constraints can be inferred and which geometry they should be inferred from

16. Select Objects Selecting Objects Deleting Objects individually objects
multiple objects
color change
Deleting Objects
right-click Delete
TECHNICAL NOTES
Scrubbing: Brush the cursor along the line or curve you want to constrain to, then move the cursor into the approximate desired position. In cases where more than one constraint is possible, this technique overrides a default constraint in favor of the constraint you selected.
Precise input: enter exact coordinates for sketch geometry as you sketch.
Selecting geometry:
Click and drag left to right to select all geometry completely enclosed in the selection window.
Click and drag right to left to select geometry enclosed and intersected by the selection window.

17. Measure Tools Measure Distances Angles Loops Area Region Properties
Points
Edges
Faces
Parts
Angles
Loops
Area
Region Properties

18. Measure Tools Measure Additional Options
Click the arrow in the Measure dialog box
Reset
Clears the contents of the measurement box
Add to Accumulate
Adds the measurement in the measurement box to the accumulate
Clear Accumulate
Clears all measurements from the accumulate sum
Display Accumulate
Displays the sum of all measurements added to the accumulate
All Decimals
Changes the decimal display between all decimals and the number of decimal places specified in the document settings

19. Exercise 2-1 Exercise 2-2 Creating A Sketch with Lines
Creating a Sketch with Tangencies

20. Constraining the Sketch
Step 2 - Geometric Constraints
Apply behavior
Create relationships
Status Bar
Fully constrain
Use projected origin point
Constraint Types
12 geometric constraints
TRAINER NOTE
Encourage students to view the Learn About Constraints video on the Getting Started screen. Click File>Getting Started>Learn About Constraints.

21. Constraining the Sketch
Geometric Constraints
Dragging a Sketch
Constrained or Not
Geometry stretches
Showing Constraints
Show all & Hide all F8 and F9
To see applied constraints
Objects change color
Deleting Constraints
Right-click or Delete key
TECHNICAL NOTES
Constraints are automatically inferred as you sketch. Add only the minimum number of constraints needed to control the sketch shape.
Use Show All Constraints to identify which constraints have been inferred. If you want geometry to have a different constraint, delete the unwanted constraint and reapply a different constraint.

22. Construction Geometry
Sketch tab > Format panel
Add dimensions and constraints
Not visible when a feature is created
Always available in the sketch
TECHNICAL NOTES
Constraints are automatically inferred as you sketch. Add only the minimum number of constraints needed to control the sketch shape.
Use Show All Constraints to identify which constraints have been inferred. If you want geometry to have a different constraint, delete the unwanted constraint and reapply a different constraint.

23. Sketch Degrees of Freedom
To see the open degrees of freedom in a sketch
Right-click and click Show All Degrees of Freedom

24. Exercise 2-3
Adding and Displaying Constraints

25. Adding Dimensions Manually
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
Arc
TECHNICAL NOTE
Sketch tab of the Application Options dialog box: select Edit dimension when created option to immediately open the edit dimension box. To edit dimensions later, clear the check box.

26. Adding Dimensions Dimensioning Arcs and Circles
Default: Arc = radius
Default: Circle = diameter
Linear Diameter Dimensions
Revolved part
Represent a quarter outline
Axis of rotation
Dimensioning to a Tangency
Arc or circle
Constraint symbol changes
Two quadrants
TECHNICAL NOTE:
Diametric dimensions are created by default if a centerline is included in the dimension. For example, sketch a profile to revolve and change the axis of revolution to a centerline style. When you apply a dimension, the value displayed is the width of the revolved profile.

27. 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
Fractions

28. 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

29. Adding Dimensions Auto Dimension Automatically apply
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

30. Exercise 2-4
Dimensioning a Sketch

31. Move and Scale Tools Move sketch objects to another location
Move or make copy
Scale a sketch
Enter scale factor
Pick two points
Relax dimensions
Relax constraints

32. Opening/Importing AutoCAD Files
Copy to clipboard within Inventor or 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)

33. Importing Other File Types
DXF
Alias
IDF Board File
IGES JT
Parasolids Binary Files
Parasolids Text Files
PRO/Engineer Files
SAT
STEP
SolidWorks Files
UGS NX Files

34. Exercise 2-5
Inserting AutoCAD Data

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

36. Checking Your Skills
True__ False__ When you sketch, constraints are not applied to the sketch by default.
True__ False__ When you sketch and a point is inferred, a constraint is applied to represent that relationship.
True__ False__ A sketch does not need to be fully constrained.
True__ False__ When working on an mm part, you cannot use English (inch) units.
True__ False__ After a sketch is constrained fully, you cannot change a dimension’s value.
True__ False__ A driven dimension is another name for a parametric dimension.
True__ False__ Dimensions placed dynamically are not parametric.
True__ False__ You can import only 2D AutoCAD data into Autodesk Inventor.
Explain how to draw an arc while in the Line command.
Explain how to remove a geometric constraint from a sketch.
Explain how to change a vertical dimension to an aligned dimension while you create it.
Explain how to create a dimension between two quadrants of two arcs.