Bezier Spline Plug-In - Courbette Tool - symmetrical spirals

[k_drive]

I have the Bezier Spline plug-in for SketchUp. I have been trying to find a way to use the Courbette Tool to make a symmetrical spiral. I could not find instructions online anywhere in a forum, webpage or on YouTube to do this. After working with the Tool for awhile, I figured it out.

Start at the Origin. Make a line one foot long along the Green or Red Axis. Move/copy it nine times end-to-end to create a ten foot long line with ten segments.

Rotate/copy the line twice at a ninety degree angle using the Origin as the pivot point. Hide the Axis so you can see the lines. Orbit your view so you have an upside down “T”. See 1. on the diagram linked below. These are your guidelines.

Select all the lines and Group them. If you don’t they will become part of the spiral.

Select the Courbette Tool. The Measurements field will show “202,24s”. I changed this to “202,48s” to create more sides for a smoother curve. See 2. on the diagram.

To start creating your spiral click on the left-most point. See 3.

Move to the top point and click. See 4.

Move to the right-most point and click. See 5.

You now want to click back and forth alternating between the left line segments and the right line segments moving one line segment inward each time. See 6. Note: Watch the smart tags as you find the next point to click on. You want to make sure you are using the “Endpoint in a Group” points and not the “Midpoint in a Group” points. See the second diagram.