Hi,

I am looking for an efficient way to create a spiral that follows the inner outline of a closed curve with a defined distance between the lines.

For example, starting from the upper-left corner of a rectangle, the spiral would follow the shape’s interior outline, continuing inward turn by turn at a specific offset distance.

Could you suggest a method or tool to achieve this?

Thanks,
Joerg

Hi Joerg,

re:
> For example, starting from the upper-left corner of a rectangle, the spiral
> would follow the shape’s interior outline, continuing inward turn by turn at
> a specific offset distance.

Can you make a rough sketch of it?

Thanks,
- Michael

Hi Michael,

Thanks for your message!

I attached an example with a simple rectangle as closed curve and created the spiral manually with the Offset function, added short connection lines, trimmed the offset rectangles and joined the lines to a single spiral curve.

Cheers,
Joerg

Hi Joerg, so kind of like the snake or Tron lightcycle games where a path is grown leaving a trail behind which you don't want to run into?

Is it required that the closed curve must be made of line segments and not a continuous smooth curve? What if the closed curve is a circle for example?

One thing I noticed is if you put in diagonal lines like this:



Move the diagonal for the start down one step, a quick way to do this is to type 20 and push Enter, that will make a distance constraint active for the next point pick and then you can drag the line down one step:



You now have all the necessary structure to draw the spiral in one single polyline. Before placing the first polyline point type in r20,-20 and push Enter. That will enable an x,y offset to be applied to the next point pick:



From then on straight snap and intersection object snap will give the needed points:







- Michael

Thanks Michael,
a good idea with the diagonal lines for the example (rectangle).

The problem is that I'm looking for a solution that is also working for closed curves that were designed with a Freeform line. Here the the line behind the outline needs to be a child of the outline. Next line needs to be a child of the first child, etc.

I had in mind that such a function was/is existing in MoI or as script from Max Smirnov.

But thanks a lot for your trying to find a solution,

Joerg