SolidWorks 2011 Parts Bible - Matt Lombard [124]
Chapter 8: Selecting Secondary Features
In This Chapter
Defining and creating curves in SolidWorks
Choosing an occasional specialty feature
Creating a wire-formed part tutorial
When you need to create features that are somewhat outside of the mainstream, you may need to reach deeper into the depth of the SolidWorks toolbox. SolidWorks has a lot of functionality that lies out of the public eye that in certain situations may be just what you are looking for. You will probably not use the tools you find in this chapter every day, but knowing about them may mean the difference between having capability and not having it.
Creating Curve Features
Curves in SolidWorks are often used to help define sweeps and lofts, as well as other features. Curves differ from sketches in that curves are defined using sketches or a dialog box, and you cannot manipulate them directly or dimension them in the same way that you can sketches. Functions that you are accustomed to using with sketches often do not work on curves.
The curve features that this chapter deals with are:
• Projected curve
• Helix and Spiral
• Curve Through XYZ Points
• Curve Through Reference Points
• Composite curve
• Imported curve
Several features that carry the curve name are actually sketch-based features:
• 3D sketch
• Equation driven curve
• Intersection curve
• Face curves
Split Line is another feature that can create edges on faces that can be used like curve features. Split Lines are not even remotely considered curves, but they can function in the same way in some situations, so this section discusses the Split Line along with the rest of the curve and other curvelike features.
Of these, the Projected and Helix curves are by far the most used, but the others may be important from time to time. Curve functions do not receive much attention from SolidWorks. Updates to curve features are few, and in some cases the functions are buggy. The usefulness of curve features is limited in the software, but in some cases there is not another good way to achieve the same result.
Tip
When you come across a function that does not work using a curve entity, but that works on a sketch (for example, making a tangent spline), it may help to use the Convert Entities function. Converting a helix into a 3D sketch creates a spline that lies directly on top of the helix and enables you to make another spline that is tangent to the new spline.
You can find all the curve functions on the Curves toolbar or by choosing Insert⇒Curve from the menu.
Curve features in general have several limitations, some of which are serious. You often have to be prepared with workaround techniques when using them. When curves are used in features, you often cannot reselect the curve to reapply sketch broken sketch relations. (The workaround for this is to select the curve from the FeatureManager, or if that doesn't work, you may need to delete the feature and re-create it). In addition, curves cannot be mirrored, moved, patterned, or manipulated in any way. (A workaround for this may be to use Convert Entities to create a sketch from the curve, or to create a surface using the curve, and pattern or mirror the surface, using the edge of the surface in place of the curve feature.)
Working with Helix curve features
The Helix curve types are all based on a circle in a sketch. The circle represents the starting location and diameter of the helix. Figure 8.1 shows the PropertyManagers of the Constant Pitch and Variable Pitch helix types.
You can create all the helical curve types by specifying some combination of total height, pitch, and the number of revolutions. The start angle is best thought of as a relative number. It is difficult to predict where zero degrees starts, and this depends on the