SolidWorks 2011 Parts Bible - Matt Lombard [111]
• Clear All. Clears the current selection set.
• Push Pin. Keeps the SmartSelection window available, even when it is not required for sketch entity selections.
• Select Closed Loop. You can select two different types of loops with this tool:
• A parametric closed loop in a 2D or 3D sketch
• A parametric loop of edges around a surface
• Select Open Loop. Selects a chain (end-to-end sketch entities).
• Select Group. Selects entities individually. If you click the Propagate symbol, all tangent edges are selected.
• Select Region. Works like the Contour Selection described earlier in this chapter.
• Standard Selection. Disables special functions of the SelectionManager. This feature works like a regular selection tool.
• Auto OK Selections. Becomes enabled when you use the Push Pin. Auto OK Selections works for closed and open loop selection.
Choosing loft options
You can choose from the following Loft options, as shown in Figure 7.17:
FIGURE 7.17
Loft options
• Merge tangent faces. Merges model faces that are tangent into a single face. This is done behind the scenes by converting profiles into splines, which make approximations but are smoother than sketches with individual tangent line and arc entities.
• Close loft. The loft is made into a closed loop. At least three loft profiles must exist in order to use this option. Figure 7.18 shows a loft where the Close Loft option is used, and the loft sections are shown. This model is on the DVD with the filename Chapter 7 — Closed Loft.sldprt.
Figure 7.18
A closed loft
• Show preview. Selecting and deselecting this option turns the preview of the Loft feature on or off, respectively, if the feature is going to work. All the following loft preview options are system options and remain selected until you deselect them.
• Transparent/Opaque Preview is available from the RMB menu when you edit a loft, if the SelectionManager is not active.
• Mesh Preview is also available on the same RMB menu.
• Zebra Stripe Preview is also available on the same RMB menu, and is covered in more depth in Chapter 12.
• Merge result. Merges the resulting solid body with any other solid bodies that it may contact.
Workflow
The workflow for the Loft feature is as follows:
1. Create or have available a set of profiles, including sketches or faces. All sketches must be closed loop and not active.
2. Select profiles and guide curves as necessary.
3. Select the required options as the situation requires.
4. Click OK to accept the feature.
Controlling Sweep features
The Sweep feature uses multiple sketches. A sweep is made from a profile (cross-section) and a path, and can create a boss or a cut feature. If you want, you can also use guide curves. Sweeps can run the gamut from simple to complex. Typical simple sweeps are used to create wire, tubing, or hose. Sweeps that are more complex are used for creating objects such as bottles, involutes, springs, and corkscrews.
The main criteria for selecting a sweep to create a feature are that you must be able to identify a cross-section and a path. The profile (cross-section) can change along the path, but the overall shape must remain the same. The profile is typically perpendicular to the path, although this is not a requirement.
Using a simple sweep
An example of a simple sweep is shown in Figure 7.19. The paper clip uses a circle as the profile and the coiled lines and arcs as the path.
FIGURE 7.19
The sweep profile follows the path.
Using a sweep with guide curves
Sweeps that are more complex begin to control the size, orientation, and position of the cross-section as it travels through the sweep. When you use a guide curve, several analogies can be used to visualize how the sweep works. The cross-section/profile is solved at several intermediate positions along the path. If the guide curve does not follow the path, the difference between the two is made up by adjusting the profile. Consider the following example. In this case, the profile is an ellipse, the path