A drafted surface is a common surface built for the mold making industry. A drafted surface models the draft angle on a mold. This surface can be thought of as a special instance of a Ruled Surface because drafted surfaces are defined with straight-line rulings for the cross curves of the surface.

In KeyCreator, a drafted surface is defined by selecting a set of profile curves and entering an angle and distance to extrude the boundary curves to locate the termin ating end of the surface.

Using the Function:

1. Select Draft from the Create>Advanced Surfaces menu. The Draft Surface dialog box appears.

2. Enter the parameters in the dialog box that will affect how the Draft Surface is created. When finished, choose OK to close the dialog box. 

3. Next select the curves from which the draft surface will be created. When selecting more than one curve, the curves must be contiguous. Note: Since one smooth surface will be created, if the curves selected do not meet smoothly (tangentially) then all sharp corners are replaced with a very small fillet radius. This may give unexpected results.

4. The control curves can be defined in three ways and the user must select one of these three methods from the dialog box. When selecting planar curves, the zero draft angle is perpendicular to the plane of the curves. When selecting non-planar curves, a vector direction must be specified to indicate the zero draft angle direction. When drafting from curves on surface, the zero draft angle is determined by the surface normal.

5. The draft surface may be modified interactively by using the buttons on the conversation bar. The surface angle and length may be changed and the display of the surface updated dynamically. Choose DONE to accept the surface.

6. The Increment option pops up another dialog box where you can alter the draft angle and surface length.