Adding Constraints to the Sketch
1
From the Sketch toolbar, select Constraint ().
This activates the smart constraint mode where you can constrain geometric entities by selecting them in the Graphics window. Depending on the geometry and selected entities, a constraint is automatically suggested by the software. You may choose to apply the suggested constraint or change it to a different constraint.
2
From the Graphics window, select the two edges highlighted below.
The perpendicular constraint is suggested, and its symbol appears under the pointer.
3
Click in the Graphics window, close to the selected edges, to place the symbol for the perpendicular constraint. You can always drag the symbol to adjust its position after placing it. The drawing is updated right away.
Note that in the Model Builder, the Perpendicular 1 node has been added under the geometry sequence. Similar to all other geometry features, you can select the node to change its settings.
4
Select the circular arc and straight edge highlighted below.
5
Click on the canvas close to where the edges meet to apply the suggested tangent constraint.
6
Continue with selecting the next straight and circular edge segments, then apply the suggested tangent constraint.
7
Next add constraints to position the centers of the circular arcs to lie on the two straight edges. First select the horizontal edge and the center of the circular arc to the right, apply the suggested coincident constraint, then repeat for the remaining arc and the vertical edge.
The geometry should now look similar to the one displayed below.
You have now applied the constraints needed to define the relations between the entities in the drawing.
8
Right-click in the Graphics window, and from the context menu choose Constraint to exit the smart constraint mode.
9
Test again to drag an edge or a vertex of the geometry. Note how the relations prescribed by the constraints are maintained as you do this.
The goal when applying constraints and dimensions is to obtain a fully constrained sketch that is not possible to modify by dragging in the Graphics window. Such a geometry is called well defined. The bracket geometry is currently still underdefined. It is not recommended to leave a sketch in an underdefined state as several solutions exists, and modifying a dimension, for example by a parametric sweep, may lead to unpredictable results.
10
Press Ctrl+Z as needed to undo any changes to the sketch.
11
To check how many more constraints or dimensions are needed until the geometry becomes well defined, click the Geometry 1 node in the Model Builder.
As you can see from the information in the Settings window the geometry is underdefined, and it needs 9 more constraints or dimensions. The rigid body translational and rotational degrees of freedom are not yet locked, meaning that the entire sketch can be moved around freely as a rigid body. To lock the rotational degree of freedom you can for example apply the Vertical or Horizontal constraints to an edge.
12
In the Graphics window select the edge highlighted below, then right-click and from the context menu choose Vertical ().
13
To check the status of the geometry in the Model Builder click the Geometry 1 node.
Only 8 more constraints or dimensions need to be applied until the geometry becomes well defined.