Offset Problems

I'm having trouble offsetting curves that roll in 3D. These same curves offset easily when baked and offset manually in rhino. I've read a good deal of the archives related to this problem and am wondering if there is a way to add a vector parameter to the offset component to replace the point pick hint that you give rhino when modeling manually? Or have these problems been resolved and I'm missing something?

Replies to This Discussion

Permalink Reply by Pieter Segeren on March 14, 2011 at 9:05am

Hi Matthew, I think I got a workaround.

Attachments:

Offset3DCurve.ghx, 77 KB

Permalink Reply by Matthew Gilbride on March 14, 2011 at 10:04am

Thanks Pieter,

Nice approach. At the moment I only see it offsetting to the inside of a closed curve. But I imagine that could be fixed. I also get weird behavior from the sweep command. It will only evaluate the sweep at a couple distinct values along the slider. That makes no sense to me. I have to play with it more and see what the issue is.

Permalink Reply by Andrew Heumann on March 14, 2011 at 10:33am

Here's a script that uses a different offset method than the one in the normal offset component. It takes a curve to offset, an offset plane, a point defining the offset direction (like where you click in the rhino offset dialog) and an offset distance.

Attachments:

OffsetByPoint.ghx, 63 KB

Permalink Reply by Matthew Gilbride on March 25, 2011 at 8:41pm

Andrew,

This component/ definition has been fantastic. In the end it has solved a lot of problems for me. Many thanks.

Matt

Permalink Reply by Andrew Heumann on March 26, 2011 at 8:44am

Glad it has helped!

Permalink Reply by Victor Leung on March 29, 2011 at 11:43am

Hi Andrew,

Hi David too,

I don't understand why the offset command in C# work so perfectly while the one in GH really suck. I had a bunch of 4 point polygon, (projected to XY to ensure planarity, rebuilt again by the vertex, so they should be very clean) half of them fail on GH offset component.

The line in C# by Andrew had all of them nicely done.

I don't understand? Aren't the libraries the same?

Cheers

Victor

Permalink Reply by Pieter Segeren on March 14, 2011 at 10:59am

Hmm, I used an open curve to make the previous definition. I don't know (anybody..?) why this doesn't work with a closed curve though.
But I made some changes. Any comments are welcome!

Attachments:

OffsetClosed3DCurve.ghx, 96 KB

Permalink Reply by Matthew Gilbride on March 14, 2011 at 2:48pm

Andrew,

Thanks much for this. Am, looking forward to trying it out when I get home. Sounds like just what I need.

Matt

Permalink Reply by Matthew Gilbride on March 14, 2011 at 2:49pm

Pieter,

Thanks to you as well. Again, I'll take a look at what you sent shortly.

Matt

Permalink Reply by Matthew Gilbride on March 14, 2011 at 5:48pm

Andrew, Pieter

These both work very nicely. Andrew your solution gives a nice amount of control over how the curve offsets and easily offsets to either side by evaluating the midpoint of each circle instead of using the endpoints. Thanks!

Matt

Permalink Reply by Thomas J. Mrokon on April 25, 2012 at 3:54am