Connecting to surfaces at random positions

harry_keith

This is my project: https://cad.onshape.com/documents/0ad00bef1bbb1f9e40173621/w/cacf7fdddd4a43435a983178/e/e7fba3ccf96226bc7bcc60d8

The objective is two "grommets", one going into a ceiling, one into a wall. The one in the wall is offset slightly from the one in the ceiling. I want to connect them with essentially a right-angle pipe elbow. Making them solid and lofting the outer surface creates an almost straight line connection, not what I want. (As an aside, lofts are terribly frustrating — they "should" do what I want, but more often than not, they don't).

Is there some way to connect these (as a solid, if necessary) where I can specify constraints (like "normal to starting surface") and have it create a smooth transition? In real life, a piece of rubber tubing, slipped over each end fitting, would create my desire outcome.

robert_scott_jr_

Stern light offset looks good. Problem fixed or is the problem somewhere else? Don't see anything else that fits your description. - Scotty

martin_kopplow

If you're after a right angle pipe elbow, then instead of a loft, a sweep might be your best bet.

harry_keith

Well, I found a solution that at least works.

On each starting pipe, create a sketch with a point at the pipe center.

Create a 3D Bezier curve (custom feature). Use control points, in order: Center point of first face, a point normal to the face, a point normal to the second face, and a point on the final face.

Create a sweep using one of the pipe faces as the face to sweep, and your Bezier curve as the path.

I'll have to play with the pipe sizes, as the sweep doesn't change sizes as it goes. But I can make it such that the start and end faces are the same size.

Fun stuff!

harry_keith

Hmm… I thought I posted that I had made a solution.

Scotty — yes, it looks good now.

Martin — I ended up using a sweep. It's not a simple right angle, which was the problem.

Long answer:

I used the 3D Bezier custom feature. I started from a point in the center of one pipe, through a point normal to that, through a point normal to the other pipe, ending at the center of the other pipe. Then swept the first pipe along the bezier to the other. My pipes are not the same size, so I had to do a little finagling, but it came out really well.

Just in case the link doesn't show the current construct, here it is again: https://cad.onshape.com/documents/0ad00bef1bbb1f9e40173621/w/cacf7fdddd4a43435a983178/e/e7fba3ccf96226bc7bcc60d8?renderMode=0&uiState=6a22f5d1e37af70044ff12e3