Can spirals be done in Sketchup?

[Jamey Amrine]

I want to add a barley twist feature to a leg spindle. I am a newbie (like in hours) with Sketchup, so please excuse me if this is a dumb question. I am well versed in parametric CAD, but parametric Sketchup is not.

-Jamey

[Dave Richards]

Yeah, sure, you can make spirals like a barley twist. There are several ways to do it. I did a coil spring example for someone yesterday using a couple of Ruby scripts. One is called Helix.rb and the other is Tube Alnog a Path.rb These scripts are free and make it very fast.

[Jamey Amrine]

I have successfully generated the spiral from helix.rb. Now how might I sweep my profile around the helix? Does this require an additional script?

Sorry if these are elementary questions.

Just to throw my thought process out there, i was thinking if I could use a profile to cut away the material I don't want along the spiral path (just as you would in real wood). Is this the correct approach?

-Jamey

[Dave Richards]

You can either sweep away the waste or add material to the base form.

Some profiles are harder to work with than others and so the way you go about working with it might need to change.

I used a second script to make the spring but it only does circles and polygons so you can't use it for a special profile.

Remember there's Intersect with model so you can draw the profile separate from the cylinder and bring the two together. Run Intersect with model and delete the waste. Sometimes that is easier than going right for the profile.

These were both made from the same cylinder and spiral. I exploded the spirals after pulling the cylinders to height. Then I ran Intersect with model and deleted the waste. For the form on the left, I shifted to wire frame so I could get easily get inside to delete the un-needed geometry in there.