topic Re: Sweep function doesn’t work in AutoCAD Forum

Sweep function doesn’t work

ksporry — Fri, 13 Nov 2020 14:10:01 GMT

Hi guys,

I’m trying to make an M10 screw thread, but can’t figure it out.
i created a cylinder. I pulled a helix over the cylinder. The helix has a turn height of 1.5mm (m10 pitch), radii of 5m, and a height of 30mm (same length as the cylinder I pulled it across) I’m now trying to sweep the helix using a predefined profile (the triangle shape on the screenshot). The way I use the sweep function is by selecting sweep, select the object to sweep (in this case the triangle), then I set alignment to “no”, and I set base point to be the top corner of the triangle shape. I then select the helix as the sweep path. I get an error stating “profile curve may not be selected as path curve” (see screenshot).

What am I doing wrong?

Re: Sweep function doesn’t work

dbroad — Fri, 13 Nov 2020 15:15:54 GMT

It would be easier to diagnose with the drawing. Here are some questions:

Is the triangular profile a closed polyline?
Why aren't you allowing AutoCAD to align the profile to be perpendicular to the path? If you don't, then you will need to manually orient it to the path, not just leave it in the xy plane.

Re: Sweep function doesn’t work

leeminardi — Fri, 13 Nov 2020 20:43:42 GMT

Start with a cylinder and a helix. The radius of the helix (red) is smaller than the radius of the cylinder.

CReate a closed polyline profile of the thread shape (yellow) and position it at the start of the helix being careful to orient it on a plane that contains the centerline of the cylinder and the endpoint of the spline. The white line was used to help define the UCS and position the shape.

Sweep the shape along the spline.

Subtract the swept profile from the cylinder.

Use the Windows snipping tool to make screen captures. It's better and easier than using a camera!

Re: Sweep function doesn’t work

ksporry — Sun, 22 Nov 2020 21:39:42 GMT

Thanks all,

I think one of the problems was that the lives weren’t all connected. I found through the use of pedit that failed. The pedit command gave me the “close” option, and I’m assuming it did that because the polylines weren’t all connected.
It could also be that the surface I used to sweep would end up touching each other when being sweeped. So I made that surface smaller, and managed to sweep it.