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Working with Sketch Plane (Solid Thinking SolidWorks Tutorial)

11 Jan, 2006 By: Greg Jankowski Cadalyst

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Learn how to work with the Sketch Plane tool to combine 2D and 3D sketches.

Sketches are the foundation for creating features in SolidWorks. You have the option of creating 2D or 3D sketches. A 2D sketch is limited to a flat, 2D sketch plane. A 3D sketch can include 3D elements. Many sketches require only 2D data to drive a part feature. But sometimes you need 3D sketch data (in routing, for example).

So why combine these features? First you can create a feature (i.e., loft, sweep) that uses multiple sketches in one sketch. Figure 1 shows a 3D sketch with multiple splines and a 2D arc sketched on Plane8. All the sketches need to define the feature are contained within the single sketch. The other, more obvious, advantage is that a 3D sketch can contain non-2D sketch elements and are not constrained to a single 2D plane.

To create a 2D or 3D sketch, click on the 2D or 3D sketch icons (figure 2). When creating a 2D sketch, the program will ask you to select a plane or face as the sketch plane.

When creating a 3D sketch, you can use a 2D plane to create 2D sketch entities. These sketch planes are defined in a similar manner to reference planes with the exception that sketch plane is embedded within the sketch. Figure 1 shows two sketch planes, Plane6 and Plane8. SolidWorks displays sketch planes using hidden lines. A regular reference plane displays using a solid font.

Creating a 2D Sketch Plane in a 3D Sketch
To add a 2D sketch entity to a 3D sketch, you have two choices: either pre-select a face or create a 2D sketch plane. The advantages of creating the 2D plane is that SolidWorks uses the sketch plane as the sketch reference until it is de-selected (see next section) and it is clear what part of the sketch is included within the 2D section of the section. You can, and most likely will, have multiple 2D sketches within the 3D sketch if you are creating a loft feature.

To create a 2D Sketch Plane, open the 3D sketch, right-click and select Plane (figure 3).

Then the Sketch Plane PropertyManager allows for three references to define the sketch plane (figure 4).

You can also create a sketch plane by selecting a plane or flat part face, right-clicking and selecting 3D Sketch On Plane. SolidWorks creates the sketch entities on the selected plane or face (figure 5). The disadvantage is that a sketch plane is not displayed like the method described above.

Then you can add the last loft profile by sketching an arc on the 2D sketch plane. Figure 6 shows a sketch plane defined through (coincident) the construction line and parallel to the right plane.

Working with 2D Sketches in a 3D Sketch
When working with 2D sketch planes within a 3D sketch, SolidWorks gives you visual clues as to what sketch plane is active and what sketch entities are included within the 2D sketch. Notice that figure 6 highlights the sketch plane and the sketch entity (arc). This shows the 2D sketch is active and any further sketching occurs on that plane.

To activate the sketch plane in the 3D sketch, you can either double-click the sketch plane or one of the sketch entities created on the sketch plane. To de-select the sketch plane, just double-click in a blank area of the graphics window or right-click and de-select 3D Sketch On Plane.

A current limitation is that once the sketch plane is defined, you can only change it by editing the relations (parallel, coincident, etc.) created when the sketch plane was inserted.

Conclusion
If you need to define sketches using 3D information, the ability to use 2D sketches adds flexibly to the design and allows you create 3D sketch entities as well as define and constrain 2D elements into the same sketch as needed.