help with simple modeling problem, sweep along path - eliminating rotation

Hi

I am having a problem with a basic modeling operation - that may have nothing to do with GH. I have a series of curve paths - that curve in all directions - and I would like to sweep a rectangular section across them but maintain their orientation along the path's length. More concretely, I want the horizontal length to remain parallel with the xy plane of the model so that this surface could represent a path or walkable surface.

I have played around with the various ways of producing perpendicular planes to the curves or frames and then adding an "align planes" component but invariably there are always some planes that are rotated 90 degrees to the others. This is the most troubling part of the modeling issue, but I am slo wondering if I should be sweeping along a path or placing the section at intervals and then lofting.

I realise this might seem really elementary...but I'm not sure how to deal with it.

Thanks so much in advance.

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Replies to This Discussion

Permalink Reply by Gabriel on May 20, 2009 at 6:47pm

David, or any other GH pros out there, is there an equivalent to the options in the typical Sweep1 rail?

I am looking for the 'style' option called roadlike:top. Or, if you could suggest a way to get the same result, I could really use the help.

Thanks!

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Permalink Reply by Chris Gignoux on May 20, 2009 at 10:52pm

This is the same essential problem I have been having except I was extruding along a path instead of sweaping. Sometimes the z-axis maintains, sometimes it doesn't....

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Permalink Reply by June-Hao Hou on May 21, 2009 at 5:39am

Use Divide Curve or Horizontal Frames component to get points on the rail curve, then use Move tool to make copies of the section curve and place them on these points. In this way, all the section curves remains their original orientation.

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Permalink Reply by Chris Gignoux on May 21, 2009 at 9:32am

I literally have hundreds of curves to extrude along is there a simpler way to ensure the proper rotation?

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Permalink Reply by Gabriel on May 21, 2009 at 11:37am

I might be misunderstanding your suggestion - i believe I have done exactly what you are suggesting, in fact bettering it by using the perpendicular frame and constructing my geometry at each of those frames... - the problem with your particular suggestion is that nothing ensures that the section is perpendicular to the rail curve. Like I said, I can do the perpendicular section part, it's ensuring that each one stays level so that in plan view there is no twisting, or banking

if I'm overlooking something, please advise. thanks

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Permalink Reply by Gabriel on May 21, 2009 at 11:42am

ok. so I completely overlooked vb.net and it appears I can do what I want through that - I just have to figure out how to get t going....

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Permalink Reply by Gabriel on May 22, 2009 at 9:55am

the problem still seems to be that the perpendicular frames are not all oriented the same way. There are components that will rotate or align them but still, there are some that are rotated 90 degrees to the others...

again, any advice, is really appreciated

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Permalink Reply by June-Hao Hou on May 24, 2009 at 10:02am

Check this out....

This example demonstrates something similar to roadlike:top style, though it is not good at dealing with turns with steep curvature.

Download definition: sweep roadlilke top.ghx