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3. Spars

4. Fill-In Boundary

Figure 24.19 shows the PropertyManager of the Vent feature. This is represented as a single column in the PropertyManager, but here it is split into two columns to fit the format of this book.

FIGURE 24.19

The Vent PropertyManager is used to specify the geometry of the feature.

The Vent feature also has several rules, most of which are not explained by the Help feature or the interface:

1. All sketch elements must be in the same sketch.

2. The entire feature must exist on a single face.

3. No sketch elements can hang off of the face.

4. The Fill-in Boundary may not have a nested contour.

5. You must have one rib before you can create any spars.

6. Spars and Ribs can be interchangeable as long as at least one sketch element in the rib selection crosses the boundary.

7. If Ribs or Spars have sketch elements that are not tangent (lines meet at an angle), the intersections will have notches on the ends, as if each sketch line were extruded individually (see the circular and triangular examples in Figure 24.18). As a workaround, you can remove the notches by using the Delete Face feature with the Delete and Patch option, selecting the two flat faces of the notch to be deleted.

The Boundary is the outline of the cutout. In Figure 24.20, the Boundary is the elements of the rectangle. The Ribs are the concentric circles, and the Spars are the radial lines.

FIGURE 24.20

Identifying components of a Vent feature

The workflow for a Vent feature is as follows:

1. Create a sketch that contains the Boundary, Ribs, Spars, and Fill-in Boundary. Rib and Spar sketch elements represent the mid-line of the feature.

2. Select each element of each Boundary, Rib, Spar, and Fill-in Boundary in its respective selection box.

3. Set the widths and thicknesses of each item.

4. (Optional) Change the Radius For The Fillets option in the Geometry Properties panel to add fillets to all sharp corners of the feature. If any of the fillets fail, it will not identify which corner failed; the whole feature will fail.

5. Use the Flow Area panel to calculate the open space of the vent.

6. Use the Favorite panel of the Vent PropertyManager to store commonly used settings. Favorites can be saved externally and shared with other users.

Using Plastic Evaluation Tools

The plastic evaluation tools in SolidWorks enable you to automatically check the model for manufacturability issues such as draft, undercuts, thickness, and curvature. The tools used to do this are the Draft Analysis, Thickness Analysis, Undercut Checker, and Curvature tools.

Using Draft Analysis

The SolidWorks Draft Analysis tool is a must when you are working with plastic parts. The part shown in Figure 24.21 has many of the situations that you are going to encounter in analyzing plastic parts. The Draft Analysis tool has four major modes of display:

• Basic

• Gradual Transition

• Face Classification

• Find Steep Faces

Draft Analysis is found in the View⇒Display menu and is either on or off, like the Section View tool. This is a benefit because it updates face colors dynamically as you model. It also has some drawbacks. The display method for the tool leaves the colors looking very flat, without highlights on curved faces, which makes parts — especially curved parts — very difficult to visualize.

Basic

The Basic draft analysis (with no options selected) simply colors faces red, green, or yellow. Colors may display transitioning if the draft shifts between two classifications. This transition type is shown in Figure 24.21 in the image to the right. For a clearer view of this method, look at the Chapter 24 Draft Analysis.sldprt part on the DVD.

FIGURE 24.21

Basic draft analysis results

You can perform all types of draft analysis in SolidWorks by selecting a reference flat face or plane, and setting a minimum allowable angle. In Figure 24.21, all walls have at least a one-degree draft, except for the rounded edge shown in the image to the right and the dome. Both of these shapes transition