ModifySurfaceDraft

Draft

Applies a draft angle to ruled surfaces.
Select the ruled surfaces you want to apply a draft angle to (planes, cylinders, generic ruled surfaces, etc.) . For each one, the program displays the normal indicating the positive sense of the draft angle. If necessary, you can invert this by just clicking on it. You must then enter the value of the draft angle in the Draft angle box. Lastly, select the draft plane.


Geometric conditions that must be satisfied to apply a draft angle

• The draft plane must contain the initial or final edge of the surface (the base curve of the ruled surface must therefore be a plane surface). If there are two or more surfaces, the plane must contain an entire edge of the outer boundary of each surface. If it does not, the plane is considered incorrect.
• If the surface has parameter limitations, the outer boundary must consist of four curves. In particular, the curve opposite that which lies in the draft plane must be in a plane parallel with the latter.
• The draft direction depends on the type of surface you want to apply the draft to. For example:
• generic ruled surface: linear direction;
• cylinder: the direction of the axis;
• plane: any direction.
• Any islands present are not rescaled.


• With the exception of planes, all other surfaces become ruled surfaces, suitably extended so that the original height

remains unchanged.

Insert a draft angle

1	Select the surfaces concerned and end selection.
2	Select the surfaces whose draft direction you want to invert and end selection.

4	Select the reference plane for calculating the draft angle.
5	The end result is:

Applying draft to the lateral surface of a cube

2. Click the tool or choose ModifySurfaceDraft.
3. Display the surface in wireframe mode by choosing ViewDisplayWireframe.

4. Select the four faces of the cube making up its lateral surface.

5. End selection.

6. The program displays the draft direction of each selected face. Click on each of them to invert the direction so that all the vectors point "outwards" and end selection as in step 5.

7. Type 15 in the Draft angle box:

8. Select the reference plane to be used to calculate the draft angle.

9. The result is: