SolidWorks 2011 Parts Bible - Matt Lombard [64]
Figure 4.5 shows a centerpoint rectangle that has been sketched with the centerpoint at the part Origin. This creates symmetry in both directions. You can use additional construction geometry and sketch relations to make the rectangle only symmetrical side to side.
FIGURE 4.5
Using a centerpoint rectangle to build symmetry about the Origin
Tip
To make a rectangle work like a square, use an Equal sketch relation on two adjacent sides. This only requires a single dimension to drive the size of the square.
Beginning with the rectangle you sketched in the previous section, apply one horizontal dimension by clicking the Smart Dimension tool on a single horizontal line, placing the horizontal dimension (4.00 inches), by clicking a vertical line, placing the vertical dimension (6.00 inches). The sketch is fully defined at this point because both the size and position of the rectangle have been established.
Best Practice
If you are dimensioning a horizontal line, the best way to do it is to simply select the line and place the dimension. Selecting the line endpoints can also work, but selecting the vertical lines on either side of the horizontal lines is not as robust. The problem is that if you use this third method, deleting either of the vertical lines causes the dimension to be deleted. In the first two dimensioning methods, dimensions are not deleted unless you remove one of the endpoints, which requires deleting two lines: the horizontal line and one of the vertical lines.
Making it solid
Next, click Extrude in the Features toolbar or choose Insert⇒Boss/Base⇒Extruded. In the Direction 1 panel, select Mid Plane as the end condition. SolidWorks takes the distance that you entered and extrudes it symmetrically about the sketch plane. Enter 1.00 inch as the distance.
Extrude Feature Options
The Extrude feature is one of the staples of SolidWorks modeling. Depending on the type of modeling that you do, the Extrude feature may be one of your main tools.
The Extrude interface
Extruding from a selection
The From panel establishes where the Extrude feature starts. By default, SolidWorks extrudes from the sketch plane. Other available options include:
• Surface/Face/Plane. The extrude begins from a surface body, a face of a solid, or a reference plane.
• Vertex. The distance from the sketch plane to the selected vertex is treated as an offset distance.
• Offset. You can enter an explicit offset distance, and you can change the direction of the offset.
Extruding from a surface
Cross-Reference
Surface features are discussed in detail in Chapter 20.
Understanding Direction 1 and Direction 2
Direction 1 and Direction 2 are always opposite one another. Direction 2 becomes inactive if you select Mid Plane for the end condition of Direction 1. The arrows that display in the graphics window show a single arrow for Direction 1 and a double arrow for Direction 2. For the Blind end condition, which is described next, dragging the arrows determines the distance of the extrude.
Each of the end conditions is affected by the Reverse Direction toggle. This toggle simply changes the default direction by 180 degrees. You need to be careful when using this feature, particularly when using the Up to end conditions, because if the entity that you are extruding up to is not in the selected direction, an error results.
Following is a brief description of each of the available end conditions for the Extrude feature:
• Blind. Blind in this case means an explicit distance. The term is usually used in conjunction with holes of a specific depth, although here it is associated with a boss rather than a hole.
• Up to Vertex. In effect, Up to Vertex works just