SolidWorks 2011 Parts Bible - Matt Lombard [122]
3. Exit the sketch, and make sure Instant 3D is selected. The Instant 3D icon is on the Features toolbar, and looks like a ruler with an arrow. Click the sketch in the graphics window, and pull the Instant 3D arrow to create a solid. Edit the feature (right- or left-click the feature either in the graphics window or in the FeatureManager and click the Edit Feature icon, which is the yellow and green block with a hand pointing to it). Now enter numbers by hand so that you extrude the sketch 1.000 inch using a From condition of Offset by 1.000 inch, such that the offset and the extrude depth are in the same direction. Rename this feature Bosses in the FeatureManager. Figure 7.53 shows the results of these steps.
Figure 7.53
The results of Steps 1 to 3
Note
These steps produce multiple bodies that will be merged in a later step. Multi-body parts are covered in more detail in Chapter 19. You can tell that there are multiple bodies by looking at the Solid Bodies folder near the top of the tree and expanding the folder. The bodies are listed in the folder.
4. On the Top plane, open a new sketch and draw a horizontal construction line across the cylinder, from the midpoint of one side to the midpoint of the other side. To pick up the automatic relations for the midpoints more easily, it is recommended that you orient the view, normal to the sketch, or use the Top view. It does not matter if you make the relations to the top or bottom cylinder, because the midpoints of the sides are in the same place when they are projected into the sketch plane.
5. Next, draw an ellipse (Tools⇒Sketch Tools⇒Ellipse) centered at the midpoint of the construction line and that measures .700 inches horizontally and 1.375 inches vertically. You may want to assign a relation between the center of the ellipse and one of the control points to prevent the ellipse from rotating and fully define the sketch Exit the sketch when you are satisfied with the result.
6. Show the sketch for the Bosses feature. Click the plus icon next to the Bosses extrude to show the sketch, and then right-click the sketch and select Show.
7. Create a plane parallel to the Top plane at the center of the larger circle. You can access the Plane creation interface by choosing Insert⇒Reference Geometry⇒Plane. If you pre-select the Top plane from the flyout FeatureManager and the center of the larger sketch circle from the graphics window, the interface automatically creates the correct plane. Click OK to create the plane. Rename this plane Top Boss Plane.
8. Draw a second ellipse on the Top Boss Plane. Do not draw a construction line as you did for the first ellipse; instead, you can just make the centerpoint of the second ellipse directly on top of the first ellipse's centerpoint. The dimensions should be 1.000 inch horizontal by 1.750 inches vertical. Figure 7.54 shows the results up to this point.
Figure 7.54
The results up to Step 8
Tip
When you are sketching on parallel planes that are separated by some distance and trying to pick up automatic relations, it is often very helpful to be looking “normal to” the sketch, so that you can see how other entities are projected into the sketch plane.
9. Use the Loft feature to loft between the two ellipses. Be sure to select the ellipses in approximately the same location so that they do not twist. If the loft preview accidentally twists, then use the connectors (light-blue square dots on the sketches that are connected by a straight line) to straighten out the loft.
Note
Notice that this feature joined together the other two disjoint bodies with the body that was created by the loft into a single body. This is a result of selecting the Merge Result option in the Options panel.
Tip
If you want to experiment, expand the Start/End Constraints panel and apply end conditions for the loft. This causes the loft to change from a straight loft to a curved loft.
10. Right-click all sketches that are showing, and select Hide. Do the same for the Top Boss Plane. This cleans up the display to prevent it