Activity 5.2a Geometric Constraints
Introduction
There are several types of constraints that can be applied within a 3D solid modeling program to control the geometry associated with a solid model: geometric constraints, dimension constraints, and assembly constraints. We will talk about dimension constraints and assembly constraints later in this lesson. In this activity we will explore geometric constraints.
Geometric constraints are applied in CAD programs to control geometry within sketches and enforce relationships between lines, arcs, circles, and other geometry. Examples of geometric constraints include parallel, perpendicular, concentric, and equal.
Constraints are often automatically applied by the software as you create a sketch in a CAD program. Sometimes you don’t even realize the constraints are being applied. For instance, to ensure that a rectangle always remains a rectangle in a sketch, a CAD program will automatically apply constraints when you create a rectangle using the rectangle tool.
However, you can also manually apply geometric constraints to a sketch to force the geometry to behave in a way that you intend.
In this activity you will investigate the effect that constraints have on the behavior of a sketch and try to replicate that behavior in a CAD sketch by applying appropriate constraints.
There are several types of constraints that can be applied within a 3D solid modeling program to control the geometry associated with a solid model: geometric constraints, dimension constraints, and assembly constraints. We will talk about dimension constraints and assembly constraints later in this lesson. In this activity we will explore geometric constraints.
Geometric constraints are applied in CAD programs to control geometry within sketches and enforce relationships between lines, arcs, circles, and other geometry. Examples of geometric constraints include parallel, perpendicular, concentric, and equal.
Constraints are often automatically applied by the software as you create a sketch in a CAD program. Sometimes you don’t even realize the constraints are being applied. For instance, to ensure that a rectangle always remains a rectangle in a sketch, a CAD program will automatically apply constraints when you create a rectangle using the rectangle tool.
However, you can also manually apply geometric constraints to a sketch to force the geometry to behave in a way that you intend.
In this activity you will investigate the effect that constraints have on the behavior of a sketch and try to replicate that behavior in a CAD sketch by applying appropriate constraints.
Conclusion Questions
1. Why is it important to use constraints when sketching with your 3D modeling program? Constraints are vital when sketching while using your 3D modeling program because they get rid of human error and allow you to place 2D sketches where they need to be.
2. Why are some constraints automatically applied by the software, but you must manually apply others? Some constraints are automatically applied by the software because they are already used when you place in that default shape. For example: Squares have 2 sets of parallel lines and all sides are congruent (along with other constraints). Some must be applied manually because they are not apart of the default shapes that you can use; a triangle tangent to a circle and one side parallel to a square.
1. Why is it important to use constraints when sketching with your 3D modeling program? Constraints are vital when sketching while using your 3D modeling program because they get rid of human error and allow you to place 2D sketches where they need to be.
2. Why are some constraints automatically applied by the software, but you must manually apply others? Some constraints are automatically applied by the software because they are already used when you place in that default shape. For example: Squares have 2 sets of parallel lines and all sides are congruent (along with other constraints). Some must be applied manually because they are not apart of the default shapes that you can use; a triangle tangent to a circle and one side parallel to a square.