Drawing a Compression Spring
A friend of mine e-mailed me asking for some help on how to draw a small compression spring. He’s working on a detail sketch of a small latch and wanted to add the spring. The basic process is to create a profile and a path and extrude the one around the other. The profile in this case is a simple circle and the path is a helix with varying pitch. I used a plugin called Draw Helix 1.4 but you could also use the Helix tool from the Curve Maker extension available in the Extension Warehouse. I also used TIG-Weld and because of the location of the path relative to the profile, I used Eneroth Upright extruder which is also available in the Extension Warehouse. To keep the math at a minimum, I created the path so it represents the full diameter of the spring with the profile toward the inside of it. Follow Me yields undesirable results in that situation, though, but Upright Extruder does the trick very handily.
The spring I drew is 1/4 inch in diameter and because it requires edges and faces that are smaller than SketchUp can make, I used my standard procedure for drawing tiny stuff. I made a component of the helix, copied it and scaled up the copy. I edited the copy to complete the spring and then closed that giant copy before deleting it. This left me with the spring at the correct size in exactly the same location where I began drawing it.