After drawing the sketch, you need to add geometric relations to it by using the Add Relations PropertyManager. Relations are applied to a sketch to constrain its degree of freedom, reduce the number of dimensions in the sketch, and capture the design intent of the sketch.
1. Choose the Add Relation button from the Display/Delete Relations flyout in the Sketch CommandManager, refer to Figure 4-9; the Add Relations PropertyManager is displayed, as shown in Figure 4-10. Also, the confirmation corner is displayed at the upper right corner of the drawing area.
Figure 4-9 The Add Relation button in the Display/Delete Relations flyout
Figure 4-10 The Add Relations PropertyManager
Geometric relations are logical operations that are performed to add relationships (such as tangent or
perpendicular) between the sketched entities, planes, axes, edges, or vertices. The relations applied to the sketched entities are used to capture the design intent. Geometric relations constrain the degree of freedom of the sketched entities. You can apply relations to a sketch by using the Add Relations PropertyManager.
The Add Relations PropertyManager is widely used to apply relations to a sketch in the sketching environment of SOLIDWORKS.
In SOLIDWORKS, some of the relations are applied automatically to the sketch entities while drawing.
For example, when you specify the start point of a line and move the cursor horizontally toward the right or left, you will notice that the horizontal line symbol is displayed below the line cursor. This is the symbol of the Horizontal relation that is applied to the line while drawing. If you move the cursor vertically downward or upward, the vertical line symbol for the Vertical relation will be displayed below the line cursor. If you move the cursor to the intersection of two or more sketched entities, the intersection symbol will appear below the cursor. Similarly, other relations are also applied automatically to the sketch when you draw it. These automatically applied relations are called Automatic Relations.
Tip
You can activate or deactivate the Automatic Relations option. To do so, choose the Options button from the Menu Bar; the System Options - General dialog box will be displayed. Select the Relations/Snaps option from the area on the left and select the Automatic relations check box from this dialog box. Next, choose the OK button. Alternatively, choose Tools > Sketch Settings >
Automatic Relations from the SOLIDWORKS menu. This is a toggle button.
While drawing a sketch, you will observe that two types of inferencing lines are displayed: blue and yellow. The yellow inferencing line indicates that a relation has been applied automatically to the sketch, whereas the blue inferencing line indicates that no automatic relation has been applied.
2. Select the center point of the circle on the right and then the lower endpoint of the right inclined line;
the Add Relations PropertyManager is modified and the names of the selected entities are displayed in the Selected Entities rollout of the PropertyManager, refer to Figure 4-11. Also, the relations that can be applied to the two selected entities are displayed in the Add Relations rollout of the PropertyManager, refer to Figure 4-11. Note that the Horizontal button is highlighted, suggesting that the horizontal relation is the most appropriate relation for the selectedentities.
Figure 4-11 The Add Relations PropertyManager displayed after selecting the entities Note
The names of the entities displayed in the Selected Entities rollout of the Add Relations PropertyManager may be different from those displayed on your computer screen.
The Selected Entities rollout of the PropertyManager is used to display the name of the entities selected to apply relations. In case you have selected the wrong entity to apply relation, you can remove it from the selection set of the Selected Entities rollout by selecting it again from the drawing area. Alternatively, select the entity from the Selected Entities rollout and then right-click to display the shortcut menu. Next, choose the Delete option from the shortcut menu. If you choose the Clear Selections option from the shortcut menu, all the entities will be removed from the selection set.
The Add Relations rollout of the PropertyManager is used to display the list of all the relations that can be applied to a selected entity or entities. Also, it displays the most appropriate relation for the selected entities in bold letters.
The relations that can be applied to the sketches using the Add Relations rollout are discussed next.
Horizontal
The Horizontal relation forces one or more selected lines or centerlines to become horizontal. You can also select an external entity such as an edge, plane, axis, or sketch curve on an external sketch that will act as a line to apply this relation. You can also force two or more points to become horizontal using the Horizontal relation. The point can be a sketch point, a center point, an endpoint, a control point of a spline, or an external entity such as origin, vertex, axis, or point in an external sketch. To apply this relation, invoke the Add Relations PropertyManager. Select the entity or entities and then choose the
Horizontal button from the Add Relations rollout in the Add Relations PropertyManager. You will notice that the name of the horizontal relation will be displayed in the Existing Relations rollout.
Vertical
The Vertical relation forces one or more selected lines or centerlines to become vertical. You can force two or more points to become vertical using the Vertical relation. To apply this relation, invoke the Add Relations PropertyManager and then select the entity or entities on which relation has to be applied. Next, choose the Vertical button from the Add Relations rollout. You will notice that the name of the vertical relation is displayed in the Existing Relations rollout.
Collinear
The Collinear relation forces the selected lines to lie on the same infinite line. To apply this relation, select the lines on which the Collinear relation has to be applied. Next, choose the Collinear button from the Add Relations rollout. this relation, invoke the Add Relations PropertyManager. Then, select two lines and choose the Perpendicular button from the Add Relations rollout. Figure 4-12 shows two lines before and after applying the Perpendicular relation.
Parallel
The Parallel relation forces the selected lines to become parallel to each other. To apply this relation, invoke the Add Relations PropertyManager. Then, select two lines and choose the Parallel button from the Add Relations rollout. Figure 4-13 shows two lines before and after applying this relation.
ParallelYZ
The ParallelYZ relation forces a line in the three-dimensional (3D) sketch to become parallel to the YZ plane with respect to the selected plane. To apply this relation, invoke the Add Relations PropertyManager. Next, select a line in the 3D sketch and then select a plane. Next, choose the ParallelYZ button from the Add Relations rollout.
Note
You will learn more about the 3D sketch in the later chapters.
Figure 4-12 Entities before and after applying the Perpendicular relation
Figure 4-13 Entities before and after applying the Parallel relation
ParallelZX
The ParallelZX relation forces a line in the 3D sketch to become parallel to the ZX plane with respect to the selected plane. To apply this relation, invoke the Add Relations PropertyManager. Select a line in the 3D sketch and then select a plane. Next, choose the ParallelZX button from the Add Relations rollout.
AlongZ
The AlongZ relation forces a line in the 3D sketch to become normal to a selected plane. To apply this relation, invoke the Add Relations PropertyManager. Select a line in the 3D sketch and then select a plane. Next, choose the AlongZ button from the Add Relations rollout.
Tangent
The Tangent relation forces a selected arc, circle, spline, or ellipse to become tangent to the other arc, circle, spline, ellipse, line, or edge. To apply this relation, invoke the Add Relations PropertyManager. Select the two entities and choose the Tangent button from the Add Relations
rollout. Figure 4-14 shows a line and a circle before and after applying the Tangent relation. Figure 4-15 shows two arcs after applying the Tangent relation.
Figure 4-14 Applying the Tangent relation to a line and a circle
Figure 4-15 Applying the Tangent relation to two arcs
Concentric
The Concentric relation forces a selected arc or circle to share the same center point with the other arc, circle, point, vertex, or circular edge. To apply this relation, invoke the Add Relations PropertyManager. Next, select the required entity and then choose the Concentric button from the Add Relations rollout.
Equal
The Equal relation forces the selected lines to have equal length and the selected arcs, circles, or arc and circle to have equal radii. To apply this relation, invoke the Add Relations PropertyManager.
Next, select the required entity and choose the Equal button.
Intersection
The Intersection relation forces a selected point to move at the intersection of two selected lines. To apply this relation, invoke the Add Relations PropertyManager. Next, select the required entity and then choose the Intersection button from the Add Relations rollout.
Coincident
The Coincident relation forces a selected point to be coincident with a selected line, arc, circle, or invoke the Add Relations PropertyManager. Select the required entity and then select a centerline.
Choose the Symmetric button from the Add Relations rollout.
Fix
The Fix relation forces the selected entity to be fixed at the specified position. If you apply this relation to a line or an arc, its location will be fixed but you can change its size by dragging the endpoints. To apply this relation, invoke the Add Relations PropertyManager. Next, select the required entity and choose the Fix button.
Merge
The Merge relation forces two sketch points or endpoints to merge at a single point. To apply this relation, invoke the Add Relations PropertyManager. Next, select the required entities and choose the Merge button from the Add Relations rollout.
Pierce
The Pierce relation forces a sketch point or the endpoint of an entity to be coincident with an entity of another sketch. To apply this relation, invoke the Add Relations PropertyManager. Next, select the required entities and choose the Pierce button from the Add Relations rollout.
Tip
You can also apply the relations using the Properties PropertyManager. This PropertyManager is automatically invoked, if you select more than one entity from the drawing area. The possible relations for the selected geometry will be displayed in the Add Relations rollout. Choose the relation you need to apply to the selected geometry.
Alternatively, select the entity or entities to which you need to apply the relation and do not move the mouse for a while; a pop-up toolbar will be displayed with possible relations. Select the required relation from the pop-up toolbar. You can also select the entity or entities and invoke the shortcut menu
The Existing Relations rollout of the PropertyManager displays the relations that are already applied to the selected sketched entities. It also shows the status of the sketched entities. You can delete the existing relation from this rollout. To do so, select the existing relation from the selection box and right-click to display the shortcut menu. Choose the Delete option from this shortcut menu to delete the selected relation. If you choose the Delete All option, all relations displayed in the selection box of the Existing Relations rollout will be deleted.
4. After applying the Horizontal relation, move the cursor to the drawing area and right-click to display a shortcut menu. Choose the Clear Selections option from the shortcut menu to remove the selected entities from the selection set.
5. Select the center point of the circle on the right and then the upper endpoint of the right inclined line.
The relations that can be applied to the selected entities are displayed and the Vertical button is highlighted in the Add Relations rollout.
Next, you will apply dimensions to the sketch and fully define it. After drawing the sketch and adding relations, the most important step in creating a design is dimensioning.
1. Choose Options from the Menu Bar; the System Options - General dialog box is displayed. Select the