Hi Burr, I think one thing that is causing some problems with your sweep is that you're getting the "auto-place" profile mode kicking in and it is causing some confusion there.

Auto-place mode is something that can be used for sweep which allows you to draw the sweep profiles flat on a plane and then have the sweeper move the profiles into place along the rail for you automatically.

Here's an example - say you want to create a tubular shape following the top path, with these 3 curves as the profiles:



One way to do it would be to move and rotate the profiles into place into their spots along the rail, that would look something like this:



Actually it is common for programs to need to have the profiles arranged in this way, but it can be rather inconvenient to do all that repositioning manually.

So auto-place mode is meant to allow those profiles to be selected right from their "flat" original positions and then they will get automatically moved and rotated along that rail curve for you.


The way that auto-place currently works, is that the sweeper will look at the bounding box around the rail curve. If all the profiles are outside of this bounding box, and all the profiles are planar and on a parallel plane, then it will activate auto-place mode. It so happens that your profile curves match all of this, so you are getting auto-place mode turned on. But the ordering used for auto-place mode is a left-to-right order taken from the profile's parallel plane direction, which in your case is the Right-side view. These curves are concentric from that view and not in a left-to-right order, that is why your ordering is weird.


Ok, I hope that made sense. I do want to make a more explicit control for auto-place mode in the future because it can cause problems like this when it kicks in unexpectedly.

So the solution for you in this case would be to move the profile curves up so that they are going around the rail curve instead of below them, like this:



That will turn off autoplace mode and instead the profiles will be used from exactly where they currently stand.

Or the other option if you do want to use auto-place mode is to draw your profile curves all flat next to one another in a rough left-to-right order, like in the screenshot I show above with the 3 profiles (the 2 circles and the pentagon).

Does that help explain what is happening to you in this case?

Right now your profile arrangement is kind of halfway between "direct profile positioning" and "auto-place" (because you are away from the rail) style arrangements.


- Michael