Offset closed curves consistently

Hello everyone,

I've been building user components with clusters, but I want to learn more on Python to make custom tools in my workflows. As a start, I'm trying to make a component to offset multiple curves consistently using Python.

Can anyone give me some help in making this component?

Below is my logic that I'm thinking, but I'm not sure whether it'll work or not.

Inputs: crv(curves), offsetDim(float)

import rhinoscriptsyntax as rs
import Rhino.Geometry as rg

#Get Centroid of Curves

cen = rg.AreaMassProperties.Centroid (crv)

#Get Coordinates of Centroid

coord_centroid = rs.PointCoordinates (cen)

#Offset Curves

offsetCrv = rs.OffsetCurve (crv, coord_centroid, offsetDim)

In the very beginning, Get Centroid of Curves, I get an error message.

"Runtime error (ArgumentTypeException): getset_descriptor is not callable"

I hope someone can help me on this...

Thank you.

Dongyeop

Replies to This Discussion

Permalink Reply by Paul N Jeffries on October 4, 2017 at 2:21pm

'Centroid' isn't a static property or function, so you need to create an instance of the AreaMassProperties type before you can get a value from it.

Try using 'AreaMassProperties.Compute(crv)' to create an AreaMassProperties object for the curve and then get the Centroid property from the result.

Permalink Reply by Paul N Jeffries on October 4, 2017 at 2:56pm

I think your next problem will be that you can't mix RhinoCommon and RhinoScriptSyntax in the way you're trying to there. Look up the RhinoCommon offset method and use that instead.

Permalink Reply by Dongyeop Lee on October 4, 2017 at 4:24pm

Hi Paul, thanks a lot for your reply.

Is this what you're suggesting? I'm still not clear how to get centroid points from closed curves.

AMP = Rhino.Geometry.AreaMassProperties.Compute(crv)

centroid = Rhino.Geometry.AreaMassProperties.Centroid(AMP)

I'm sorry if it doesn't make sense at all, but I hope you can let me know the answer.

Permalink Reply by Paul N Jeffries on October 4, 2017 at 5:08pm

The first line is right (probably - I haven't tested!), the second should just be:

centroid = AMP.Centroid

This is because 'Compute' is a static function on the AreaMassProperties class which will create an actual instance of that class, 'AMP'. 'Centroid' is a (non-static) property of the class, the value of which will be specific to that particular instance and must be accessed through an object of that type, rather than through the type itself. (This is perhaps no clearer for you, but this is all fairly basic Object Orientated Programming theory and I'm using the technical terms so you'll have some keywords to google!)

Permalink Reply by Dongyeop Lee on October 5, 2017 at 8:08am

I had a chance to learn about Class, but I didn't know about the term, Static.

I'm getting my feet wet in textual programming and it's great for me to get help in this forum thanks to people like you. I hope I can help others in return after sometime later.

The code below does work as I wanted!

#Get Centroid of Curves
AMP = rg.AreaMassProperties.Compute (crv)
cen = AMP.Centroid

#Offset Curves
offsetCrv = rs.OffsetCurve (crv, cen, offsetDim)

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