How to use OffsetCurve in GHPython

Hello,

I'm offsetting polylines in GHPython using rhinoscriptsyntax. rs.OffsetCurve seems to create extra points on the offsets, which is interfering with the rest of my script's logic.

I tried using SimplifyCurve to delete the extra points but that too behaves differently than the Rhino command.

Is there a workaround, or am I missing something?

Also, my script seems pretty long and clunky for such a simple task, is there a more efficient solution?

Thanks,

Max

Attachments:

GHPython_Offset.3dm, 28 KB
GHPython_Offset.gh, 4 KB

Replies to This Discussion

Permalink Reply by Ángel Linares on November 6, 2015 at 8:26am

I think that you are not using Simplify properly.

Here is the solution using Rhino.Geometry instead of rhinoscriptsyntax function:

from Rhino.Geometry import Curve as c
from Rhino.Geometry import CurveOffsetCornerStyle as ce
from Rhino.Geometry import CurveSimplifyOptions as cs

a = []

for i in range(it):

oCrv = crv.Offset(P,dist*(i+1),0.01,ce.Sharp)[0]
a.append(oCrv.Simplify(cs.All,0.01,0.1))

Attachments:

Captura.JPG, 251 KB
Simple_offset.gh, 11 KB

Permalink Reply by Giulio Piacentino on November 6, 2015 at 9:03am

Hi Max, hi Angel,

you were unlucky enough to discover two bugs (RH-31854 and RH-31855). They are not correlated.
The one with rs.Offset() is fixed in Rhino WIP, as Angel probably noticed.

I am attaching a definition that will work in Rhino, where Simplify() is called in RhinoCommon with finely-tuned arguments.

Thanks for reporting this,

Giulio
--
Giulio Piacentino
for Robert McNeel & Associates
giulio@mcneel.com

Attachments:

GHPython_Offset_workaround.gh, 5 KB

Permalink Reply by Ángel Linares on November 6, 2015 at 9:17am

But, why did you use such a long CurveSimplifyOptions call instead of a simpler one like:

Rhino.Geometry.Curve.Simplify(offset_crv, Rhino.Geometry.CurveSimplifyOptions.All, 0.01, 0.001)

This worked for me in RH5 SR12 64-bit right now.

Permalink Reply by Giulio Piacentino on November 6, 2015 at 2:40pm

Well I did not want the arc simplification nor the G1 adjustment. Arc can take precedence over lines if the arc falls within tolerance.

Permalink Reply by Max Marschall on November 6, 2015 at 10:17am

Hi, thanks for your quick responses.

Your workarounds work, although there is still some unexpected behavior:

In my particular case it'll do just fine though, thanks!

Max

Permalink Reply by Giulio Piacentino on November 6, 2015 at 2:44pm

Yes, sorry, for now what I gave you, really, is just a workaround. Grasshopper gives the same result. It's really the RhinoCommon Offset() call that works not ideally.

Thanks for the extra reminder. It would help if you could attach the sample.

Giulio
--
Giulio Piacentino
for Robert McNeel & Associates
giulio@mcneel.com

Permalink Reply by Max Marschall on November 6, 2015 at 4:14pm

Sure, here it is. (I used your definition as it was.)

Cheers,

Max

Attachments: