Can anyone tell me how best to model what I have described as a spiral tube. To imagine the shape I mean, first imagine a standard helical corkscrew. If you took a vertical section through that, the circular rod section that forms it would become an ellipse. But suppose you wanted it to be a rectangle instead. What you would end up with is something like the spiral you get when you peel an apple.
Using excellent advice from @Boxhere, I was able to produce something approaching what I wanted, as you can see:
Not quite. I have described it badly. Take a look at the way this tube is constructed:
That is made from a single width of metal. Imagine it made of two widths in line and following one another. Now take away one of them. Then add more width to the metal sheet. That is what I want to end up with.
That’s how that tube can be modeled (using FredoTools and JPP) - tbn-4.skp (88.4 KB),
but with what you want, if it’s possible, a sketch would help
I wanted to model it for two reasons. One is that it could form the structural part of a staircase. The second was just the challenge of learning to do something new. And as so often, the forum came to the rescue!
I used my Spirix plugin. This is something that I’ve quit mentioning as a solution because it’s not very intuitive to use. However, it was easy for this shape. Create a group “a1” and fill in a few obscure parameters:
