Constraints

Note: Constraints restrict a Degrees of Freedom completely. There is not a way to partially apply a constraint to an object. There are no contact or a hybrid constraints that can be applied.

Parts Workspace

In the parts workspace sketching constraints can be applied when drawing sketches. The first sketch figure that is selected is the sketch figure that is referenced when applying a constraint. This means the second sketch figure that is selected will move when the constraint is applied. Constraints are automatically shown by symbols. The size of them can be changed in the Options menu (Tools>Options) under the Drawings>Sketching menu.

Constraints in the Sketching interface define the location and position, and the value and magnitude of a sketch object. To display how much a sketch figure is defined press Ctrl+Shift+N. To open the quick define sketch interface press Ctrl+Shift+U. The Location of an object is the coordinate the object is defined as on a given plane. An example of this would be a circle’s center; the circle is defined by its center. The magnitude of an object would be the value it has been determined to be. The magnitude of a circle is the radius.

Dimensioning a sketch figure is considered a constraint. This defines the magnitude of an object. This can define the object itself or how it is located in relation to another object. The parameters for all constraints can be edited in the Equation Editor or Global parameters.

Assembly Workspace

Every part in the assembly workspace has twelve Degrees of Freedom that may be constrained. A Degree of Freedom can be defined as a direction a part can move through a linear translation or a rotation. A part, assembly or sub assembly has six local degrees of freedom and six global degrees of freedom.

It is possible to apply a constraint that constrains more than one Degree of Freedom. For example if you have a cube and you constrain one edge to be collinear with the Z axis. The cube has been constrained from moving in the X and Y directions as well as rotating around the X and Y axis. This would leave two Degrees of Freedom remaining: a Z translation and a Z rotation.

You can constrain the global coordinates by constraining objects to reference geometry in the part. When you constrain parts to other parts you are constraining local coordinates of the object.

For example you now have two blocks. Constrain two of the faces to be coplanar. Locally there are two Degrees of Freedom left unconstrained between the two blocks. Globally no Degrees of Freedom have been constrained.

You are able to constrain one object and the associating object becomes constrained. With the two block example, we make two faces coplanar, and then constrain the opposite face of the previous constraint to the X-Y plane.

This now constrains the second block to a fixed distance from the X-Y plane. This distance is the Length of the block. This has also constrained the rotational Degrees of Freedom around the X and Y axis for both blocks.

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