SolidWorks 2011 Parts Bible - Matt Lombard [15]
Figure 1.15 shows images of simple feature types along with the 2D sketches from which they were created.
FIGURE 1.15
Simple extruded and revolved features
Many different feature types in SolidWorks enable you to create everything from the simplest geometry shown in Figure 1.15 to more complex artistic or organic shapes. In general, when I talk about modeling in this book, I am talking about solid modeling, although SolidWorks also has a complete complement of surfacing tools. I discuss the distinction between solid and surface modeling in Chapter 20.
Cross-Reference
To learn more about surfacing in SolidWorks, refer to the SolidWorks Surfacing and Complex Shape Modeling Bible (Wiley, 2008) for a complete surfacing reference.
Table 1.2 lists some of the most common features that you find in SolidWorks and classifies them according to whether they always require a sketch, a sketch is optional, or they never require a sketch.
In addition to these features, other types of features create reference geometry, such as curves, planes, axes, surface features (Chapter 20); specialty features for techniques like sheet metal (Chapter 21); plastics/mold tools (Chapter 24).
Understanding History-Based Modeling
In addition to being feature-based, SolidWorks is also history based. To show the process history, there is a panel to the left side of the SolidWorks window called the FeatureManager. The FeatureManager keeps a list of the features in the order in which you have added them. It also enables you to reorder items in the tree (in effect, to change history). Because of this, the order in which you perform operations is important. For example, consider Figure 1.16. This model was created by the following process, left to right starting with the top row:
1. Create a sketch.
2. Extrude the sketch.
3. Create a second sketch.
4. Extrude the second sketch.
5. Create a third sketch.
6. Extrude Cut the third sketch.
7. Apply fillets.
8. Shell the model.
Figure 1.16
Features used to create a simple part
If the order of operations used in the previous part were slightly reordered (by putting the shell and fillet features before Step 6), the resulting part would also look slightly different, as shown in Figure 1.17.
FIGURE 1.17
Using a different order of features for the same part
Figure 1.18 shows a comparison of the FeatureManager design trees for the two different feature orders. You can reorder features by dragging them up or down the tree. Relationships between features can prevent reordering; for example, the fillets are dependent on the second extruded feature and cannot be reordered before it. This is referred to as a Parent/Child relationship.
Cross-Reference
Reordering and Parent/Child relationships are discussed in more detail in Chapter 12.
FIGURE 1.18
Compare the FeatureManager design trees for the parts shown in Figure 1.16 and Figure 1.17.
On the DVD
The part used for this example is available in the material on the DVD, named Chapter 1 — Features.SLDPRT.
The order of operations, or history, is important to the final state of the part. For example, if you change the order so that the shell comes before the extruded cut, the geometry of the model changes, removing the sleeve inside instead of the hole on top. You can try this for yourself by opening the part indicated previously, dragging the Shell1 feature in the FeatureManager, and dropping it just above the Cut-Extrude1 feature.
Note
You can only drag one item at a time in the FeatureManager. Therefore, you may drag the shell, and then drag each of two fillets, or you could just drag the cut feature down the tree. Alternatively, you can put the shell and fillets in a folder and drag the folder to a new location. Reordering is limited by parent-child relationships between dependent features.
Cross-Reference
You can read more about reordering folders in Chapter