1. Constraint Based Modeling Geometric and Dimensional
ENGR 1182
SolidWorks 03

2. Today’s Objectives
Using two different type of constraints in SolidWorks:
Geometric
Dimensional
SW03 In-Class Activity
List Geometric Constraints
Apply Geometric and Dimensional Constraints
SW03 Out-of-Class Homework Assignment

3. Constraints Geometric Dimensional Two different types of constraints:
Constraining geometry based on normal orientations or relative to other parts of the geometry
Dimensional
Numerical values that constrain the size and location of geometry

4. Geometric Constraints
ENGR 1182
SolidWorks 03

5. Geometric Constraints 2 Options
Constraints relative to the normal conventions for direction. Examples: vertical, horizontal
Constraints relative to other sketch entities.
Examples: perpendicular, parallel

6. Advanced Geometric Constraints
Accurate Models
Tangent Constraints
Arcs or Circles
Equality Constraints
Equal sizes
Concentric constraints
Align Center Points
Geometric Constraints can reduce the time it takes to create accurate models by reusing valid geometry
Tangent constraints are used to align lines with arcs or circles
Equality constraints make lengths or sizes equal between consistent entities
Concentric constraints take center points of arcs or circles (construction geometry) and makes them located at the same point

7. Automatic Constraints
Unwanted constraints can be selected (left click) and deleted (delete key)
While sketching SolidWorks will automatically guess at the constraints that the user implies
Dotted lines show alignment and icons show the constraints applied

8. SolidWorks: Selecting
Lines or points can be selected by holding Ctrl and left clicking on each
At the left of the screen relations can be added by selecting the appropriate icon
The lines will snap to the applied constraint and icons will display the current constraints

9. How Could We Create This? (with uniform thickness and aligned?)

10. SolidWorks: Applying Constraints
This edge can be selected and moved manually
Original Shape
Step 1: Horizontal and Vertical Constraints
Step 2: Make Slants Parallel

11. SolidWorks: Applying Constraints
This profile is not fully constrained but the shape is generally constrained by using only Geometric Constraints
Step 3: Equality Constraints on all similar members
Geometric constraints are used to create robust models that can alter and still remain consistent with the design intent. The designer can use dimensional constraints to finalize the design and correctly align objects to numerical values and not just associations. Geometric constraints though can greatly decrease the drawing time period and reduces the number of dimensional constraints.

12. Geometric Constraints Wrap Up
Relationships:
Vertical
Horizontal
Parallel
Perpendicular
Equal
Coincident
Circular Relationships:
Tangent
Concentric
Homework Assignment SW03-OUT:
Draw the following object and constrain with geometric constraints only. The shape will not be fully defined but should maintain shape if selected and dragged
Revised 8/10/14 by R.C.Busick to move homework image from covering the text.

13. In-Class Assignment
List all the necessary constraints to go from the initial shape to the final, then apply the constraints on the SolidWorks part file to confirm 1 8 7 2 3 6 4 5

14. Dimensional Constraints
ENGR 1182
SolidWorks 03

15. Dimensional Constraints
Linear Dimensions
Radial Dimensions
Angular Dimensions
Dimensional constraints can be added to linear dimensions such as distance between points or length of segments
Other options include radial dimensions of arcs or circles, and angular dimensions
These constraints should be used in conjunction with geometric constraints in order to create a robust model
Dimensional constraints are not unique and are left up to the designer in how they are applied to create the correct geometry

16. Once constrained with geometric constraints how do we make this accurate?

17. Design Strategy
Effective robust designs starts with shape and geometry constraints, and then dimensional constraints are added

18. Algebraic Constraints
Simple Algebraic Expressions
i.e.(type) = 20/3
Related to Other Dimensions
Driving vs. Driven
Is D5 Driving or Driven?
Dimensions can be entered as numerical values or also they can be entered using simple algebraic expressions
Dimensions also can be related to other dimensions already assigned
The primary dimension is referred to as the “Driving” dimension and the related dimension is “Driven”
A “Driven” dimension will also result if the designer tries to over-constraint a geometry that is already determined by other dimensions or constraints
D5 is driven

19. SolidWorks: Dimensions
Dimensional Constraints can be added using the Smart Dimension Button
Click on the entity
Move cursor off object
Click once more to place dimension
When Constraints are applied the following dialog box will appear displaying
Dimension Name
Editable Dimension Value
Options (direction, etc.)

20. SolidWorks: Dimension Options
Dimensions can be added between 2 lines by selecting the lines sequentially
Between a point and a line
Or even 2 points as long as the correct direction is chosen ( the Smart Dimension tool shows options when moving the mouse)
Caution: Refrain from using point to point unless absolutely necessary. This can cause a variety of problems and is not as robust of a way to apply dimensions.

21. SolidWorks: Circles and Arcs
Circles or Arcs can be dimensioned by the diameter (Ø) or radius (R)
A circle can be located by its center point by constraining both the x and y directions

22. SolidWorks: Angular Dimensions
Angular Constraints can be added by clicking one line and then the other line. SolidWorks will automatically assume angular constraint.

23. SolidWorks: Algebraic Constraints
Constraints can be added in the form of equations by:
Entering “=“
Entering a value or by left clicking on a dimension
Using operations +, -, *, /

24. Dimensional Constraints Wrap Up
Homework Assignment SW03-OUT:
Problem 6.4 (r)
Dimensional Constraints
Linear
Radial
Angular
Coupled with Geometric Constraints
Algebraic
Relations between dimensions

25. In-Class Activity
Open the seed file in the course drive. Adjust the shape using geometric constraints and then add dimensional constraints to finalize the model.
Start with the simple shape and then move on to the harder if time remains. Try to use both geometric constraints and dimensional constraints in order to quickly create the following objects.

26. Important Takeaways
Using different geometric constraints to constrain geometry based on normal orientations or relative to other parts of the geometry.
Using dimensional constraints to constrain the size and location of geometry.
Algebraic dimensions create relations between dimensions.

27. What’s Next? Due Next Class: SW03 Out of Class HW
Before next class, you will read about design intent with fully defined drawings
Also you will learn about solid modeling’s design analysis tools
Take SolidWorks 4 Quiz on readings