Extruding a Surface along a Path

This section demonstrates how the Extruded Surface entity can be used to sweep a shape curve along a patch curve.

1. Create a shape curve using a BSpline from the Create menu, (Create -> BSpline Curve).

2. On the x/y plane, draw a BSpline curve consisting of six points in a hill shape.

3. Draw a path, again using a BSpline Curve.

4. On the y/z plane, begin drawing the curve.

5. The path curve can be quite detailed in nature.

6. The curve below consists of 14 control points.

7. After drawing the curve, select the path.

8. From the Right-Click menu, choose Extrude Surface, (Right-Click -> Multiple Selection -> Extrude Surface).

9. An Extruded Surface is created by sweeping the first curve along the second curve.

10. Looking more closely, by default, the centre of gravity of the shape curve is swept along the path curve.

11. Change the colour of the surface and render.

12. The attributes panel provides several sweep options. The "Scale Shape" option enlarges the shape curve as it is swept around sharper corners.

Without this option it will appear as though the swept surface reduces in size as it is swept around sharper corners.

13. The "Rotate Shape with Path" maintains the shape curve in the same orientation relative to the path curve as it is swept.

Turning off this option maintains the shape curve in the same orientation in the world coordinate system.

14. The "Centre Shape with Path" option sweeps the surface from the location of the shape curve rather than the patch curve.

The swept surface will being at the location of the shape curve.

The swept surface will be offset some distance from the path curve.

15. If the Shape Curve and the Path curve are the wrong way around in the surface definition, they can be swapped using the button in the attributed panel.

This may lead to some strange shapes.

16. Once the surface has been generated it can be converted to a BSpline Surface using the option on the Right-Click menu, (Right-Click -> Extruded Surface -> Convert to BSpline Surface).

Creating a Coons Patch >>>