Constraint Based Modeling Geometric and Dimensional ENGR 1182 SolidWorks 03

Today’s Objectives Using two different type of constraints in SolidWorks: Geometric Dimensional SW03 Activity List Geometric Constraints Apply Geometric and Dimensional Constraints SW03 Application

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

Geometric Constraints ENGR 1182 SolidWorks 03

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

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

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

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

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

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

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.

Geometric Constraints Wrap Up Relationships: Vertical Horizontal Parallel Perpendicular Equal Coincident Circular Relationships: Tangent Concentric Application SW03 - GEO: 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.

Activity (SW03) 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

Dimensional Constraints ENGR 1182 SolidWorks 03

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

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

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

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

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.)

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.

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

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

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 +, -, *, /

Dimensional Constraints Wrap Up Application SW03 - DIM: Problem 6.4 (r) Dimensional Constraints Linear Radial Angular Coupled with Geometric Constraints Algebraic Relations between dimensions

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.

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.

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