Product:	MicroStation
	Version:	08.11.09.xxx
	Environment:	N\A
	Area:	Curves
	Subarea:	N\A

Problem

I want to create a helix curve along a specific path, but the Helix Curve tool only creates helical curves at orthogonal directions.

Solution

1. Draw the curve of the path you want the helix curve to revolve around. In the following video, the curve is green.

2. Draw a horizontal line originating from the bottom end of the curve. This will be the radius of the twist.

3. Draw a circle at the horizontal line with the center at the end of the line. The size of the circle won't matter unless it is too large, so keep it pretty small.

4. Use the Solid By Extrusion tool with the Spin set to 3600. This will ensure the solid will spin around the path 10 times total (10 x 360 deg.). The maximum amount of revolutions you can do at one time is 10, so you may have to create your spline as separate elements at first. Choose the curve (drawn in step 1) as the element for path and the circle (from step 3) as the profile. Accept. You are left with the spring shape you want, but the element is a three-dimensional smart solid.

5. Activate the Extract Iso-Curve tool (Tools>Surfaces>Surface Utilities). Select the helical solid. Select the main face of the solid once more, then accept.

6. At first, nothing will appeared to have changed, but you have created the B-spline curve you want! You simply need to delete the solid to expose the curve.

7. Boom! There's your helical curve which follows along the path you designated. 

See also

Other language sources

Original Author:

Erik Mendoza