Urgent Help on Curve offset. Please.

Dear fellow GH Users

I would really appreciate help on this problem. I am currently working on a competition scheme and everything is going to fall flat if i cant solve this problem. I have searched through the forum and tried finding an explanation that deals with the offset of curves. Some members have brought this issue up before, but for some reason i cannot understand the concept or get it to work.

The problem involves the splitting of a surface with a set of curves, then extracting the wireframes of those surfaces and then offsetting them to the inside.

I understand the concept that the direction of the curves should all be in the same direction of the surface plane etc. But i don't understand how to evaluate for that and then flip them. Also i don't know what the guide curve would be.

Please see attached images to illustrate my predicament. I have also attached the rhino 4 and GH.8.7 files of the problem.

I would deeply and sincerely appreciate any kind of help to resolve this problem.

Kind regards

Gordon

Attachments:

offset minus.jpg, 332 KB
offset.3dm, 64 KB
offset.ghx, 376 KB

Replies to This Discussion

Permalink Reply by Danny Boyes on March 18, 2011 at 8:29am

Take your pick http://www.grasshopper3d.com/page/search-results?cx=007664031582976....

EDIT: This ones probably the best: http://www.grasshopper3d.com/forum/topics/offset-problems

Permalink Reply by G on March 18, 2011 at 10:14am

Hi Danny

Thank you for the links. I have already gone thru most of them, but not finding something that works with my problem. There are some very interesting ones that works on some situations, but when i apply it to mine, it seems to go haywire. Some of them are so complex, that i have no idea how to trouble shoot them. All in due time tho, just frustrating in the interim.

Thank you again for your help (of which you bailed me out already a few times). I will keep searching thru the list you send thru till i find something.

Gordon

Permalink Reply by David Wood on March 18, 2011 at 11:39am

Gordon,

I've often found that offsetting a curve onto a surface to be much more reliable than the standard curve offset tool. Although it's seriously heavy on memory!

Worth a try if you're desperate perhaps.

Best,

David.

Permalink Reply by G on March 18, 2011 at 11:49am

Thanks David.

I will give it a shot. Problem is, there are a few hundred closed curves to offset. Going to be interesting to see what happens

Gordon

Permalink Reply by Pieter Segeren on March 18, 2011 at 12:10pm

You could scale down your subsurfaces around their (Brep Area-) centers and duplicating the edges of these scaled subsurfaces for a result NOW. But I think you'd better rethink your approach though...

Permalink Reply by RWNB on March 18, 2011 at 12:22pm

I found this definition in the forum.

how i see, the edges are not formed correctly.

maybe someone is so nice and solves this problem.

good luck

Attachments:

offset.ghx, 477 KB
offset.3dm, 72 KB

Permalink Reply by Pieter Segeren on March 18, 2011 at 2:43pm

Hi Gordon, here's my quick adaption of your definition. NB:I scaled everything by a factor of 0.01 (and the rhino file aswell). I also noticed that your subsurfaces are not square. Hope you got enough to finish what you were working on!

Attachments: