Basic geometric shapes such as cubes and cylinders are easily defined however; 3D CAD software can do much more. When a designer takes advantage of the 3D software capabilities, more complex shapes may be created and defined.
Consider a complex feature such as a compound curve. Compound curves may be defined in SolidWorks using the surfacing tool. In order to define this curve it must be constrained using three sketches. The image below contains a sketched curve on the Front, Right and Top Plane. Please note that the curve is sketched in a solid line whereas parts that do not define the curve are kept as construction lines.
Each curve may be modified to suit your chosen geometry. The numerical values in this example are arbitrary however note that each curve shares a termination point from start to finish.
Next, activate the surfaces tab and select the boundary surface tool. This tool creates a surface within the bounded conditions. In this case the bounded conditions will be the sketches. Under Direction 1 tab, select the two sketches on the Right and Front Plane.
Please note that the curve as shown is incomplete since the surface is only bound by the two sketches as reflected in the preview. The bottom edge of the surface needs to follow the contour as outlined on the Top plane sketch. To do so, activate Direction 2 and select the top plane sketch.
Now the compound curve is properly bound by all three sketches. We may now accept and apply this feature
A fully defined compound curve surface is now defined. This surface may now be used to complete a part or work as a simplified model for an FEA analysis. The tools to create 3D parts such as compound curves are all available in SolidWorks.