Which side to offset??

hi grasshoppers,

I am kind of confused on the Curve Offset component now .Today I offset two closed curves separately with the same config ,but one curve offset toward outside while the other inside .Both the guide planes are the defalut XY plane .Picture below.

howerer once I changed the both guide plane to an ohter one ,they offset towards the same side .see picture below .

I am waiting some clarification .THanks in advcance...

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Permalink Reply by David Rutten on November 7, 2010 at 9:38am

I wish I knew. I just call the Rhino SDK offsetter which takes a plane and a distance. I'll ask around in the office tomorrow.

--
David Rutten
david@mcneel.com
Seattle, WA

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Permalink Reply by Giulio Piacentino on November 7, 2010 at 9:52am

Hi Alpha,

maybe this can help: in 0.7.57 it used to work reliably, while in 0.8.001 it does not.
Since most components are the same between these two versions, you could just use the 0.7 version until a bugfix is released.

@David: I remember reading something about offset directions in RhinoCommon in the newsgroup.

- Giulio
_______________
giulio@mcneel.com
McNeel Europe, Barcelona

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Permalink Reply by David Rutten on November 7, 2010 at 7:32pm

yeah something is fishy here. I'll see what I can find out tomorrow.

--
David Rutten
david@mcneel.com
Seattle, WA

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Permalink Reply by David Rutten on November 9, 2010 at 7:42pm

There was a bug in the RhinoCommon offsetter. I fixed it, but there are still other things I'd like to change to the offset algorithm.

--
David Rutten
david@mcneel.com
Seattle, WA

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Permalink Reply by Alpha222 on November 8, 2010 at 6:09am

@David Hi David, in fact, I have lots of closed curves and one bundle of them offset incorrectly . I just baked one of them and offset it ,same incorrect result occured .And "amazing" things followed: I just drap it to another place and it just offseted correctly !! I hope this info help you find bugs out .

@Giulio Thanks Giulio for the kind advice .I just use a scale component instead of offseting .

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Permalink Reply by Suryansh Chandra on November 10, 2010 at 10:02am

Scale might give you inconsistent offset distances on each edge. Another work around could be:

1. Offset each cell in both directions (using a +ve and -ve value of the same amount for Offset Distance)
2. Check which of the two curves is shorter in Length.
3. Create a culling pattern to remove the longer ones.

Perhaps a bit tedious and maybe even slow -- but its quite robust. It only fails when the offset ends up exploding the curve.

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Permalink Reply by Alpha222 on November 11, 2010 at 8:56am

Thanks for the kind advice .I would keep this in mind .

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Permalink Reply by Alessio Erioli on November 12, 2010 at 1:45am

Hi all!

I ran into the offset issue while setting up David Fano's powercopy workflow for my students in GH 0.8.001.

What happens to me is, besides the weird flippings in the offset side, is that the offest component goes red when I feed in a Plane by 3 points, just like this:

The component message just says "curve offest failed".

Please notice that offset distance is not the problem (worked fine with XY world plane).

Hope this might help in the bug search & fix (or might turn out it's me doing something wrong... in that case hints will be appreciated..:-D).

Best,

Alessio