Sweep Problem : Wild behavior and limitation

Hello, I seem to have encountered a wild behavior for Sweep 1 command in the main interface . The image shows two sweeps made with the same parameters (Roadlike). Also I can’t achieve what I want which is a clean mitered sweep following the rail. I don’t know if my rail is just not applicable to sweep due to it’s shape, because even when using Sweep 1 in Grasshopper, instead of forming one clean sweep it creates 2 sweeps mimicking the image on the right.

The highlighted yellow curves are the rail and profile.

Where’s your GH code?

Is your rail a segmented polyline or a smooth interpolated curve? Are your section curves all going the same direction?

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I’m so sorry, I forgot to post the file. Basically the rail is 2 joined curves so it’s a segmented polyline. My goal is for the section curve to follow the rail and have a clean miter. I was wondering whether this is an inherent limitation for sweep.

Sweep Problem.gh (2.9 KB) Intersection Sweep Case Study.3dm (10.6 MB)

Your rail has a right angle in it, your section doesn’t touch the rail:

Geometry isn’t internalized for second Sweep1.

P.S. Right-click on the Swp1 ‘M’ (Miter) input and change from ‘Trim’ to ‘None’ or ‘Rotate’.

Hi joseph, thank you for your responses. Is there no way to achieve my goal with sweep? It’s the only way I can think of to make intersections and I use the very same principle to make road intersections when I’m modelling an architectural site. I even tried moving my profile to touch the rail and still it can’t make a good sweep. I attached a file showing 3 results of sweep. Right now I’m thinking to maybe try just use a boolean operation to remove unnecessary geometry from the resulted sweep but i’d still prefer a clean sweep though.

Here is an example of what I’m trying to do.

Rail Intersection

Sweep Problem 2.gh (8.4 KB) Intersection Sweep Case Study 2.3dm (10.8 MB)

If the curve is drawn properly, sweep1 work as expected. The example is as posted.Intersection Sweep Case Study 2.3dm (11.6 MB)Intersection_Sweep_case_study1.gh (12.2 KB)

Hi akche, how do you figure I draw the curve properly? It’s basically automated in grasshopper. Also what do you mean by properly? What operation should I do in grasshopper? Should I try rebuilding or refitting the curve? Thank you.

I mean the rail curve for sweep. I draw rail curve in planes perpendicular to each other as in attached image. And 1sweep component worked as expected, as you can see in the file that I uploaded in previous post. I checked the rail curve that you drawn and it was not perfectly drawn in two planes as I draw here. You only need to draw the rail curve properly as I draw here and then use it as input curve for rail in grasshopper and my gh file will work. And for profile curve, I used your profile curve but another way. Now you can edit profile curve and the sweep will still work. The profile curve is near origin.Check out files in this post.

Intersection Sweep Case Study 2.3dm (11.6 MB) Intersection_Sweep_case_study1.gh (17.2 KB)Proper_rail_sweep_modeled_without_grasshopper.3dm (10.6 MB)

Geometry isn’t internalized

About what is this statement related? It’s irrelevant if geometry is internalized or not in order to work 1rail sweep or 2 rail sweep properly. It thoroughly depends on how the rail and profile curve is drawn in rhino or in grasshopper. Refer to my two comments and files above.