Gh python: error working with coercecurve but not in Rhino python editor

Scripting
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1

Hello,

Running my script from the Rhino Python editor does not produce any errors, a similar script embedded in Gh as a component however, does:
After filtering a curve input for deg=1 , I am trying to create a vector in the direction of the lines and use its start-/Endpoint for a series of transformations.
In Gh python I get the follwing errors:
using rs.CurveStartPoint(Id): Unable to convert Id into curve

Earlier in the script I use a filter with rs.coercecurve on every id in the list, only the segments of an exploded polyline not.

Using Rhino.geo.curve.PointAtStart(Id): I get an error message working with the start/endpoin a few lines latert: could not convert property PointAtEnd to a point3d.

Fed to the script are a rectangle and four lines forming a pyramid.
I assume it has to do with the rectangle-polyline, which components should be added to the list, but the polyline id removed;

It would be amazing if you can help me pinpoint how the error can be avoided.
Any general advice or improvements are much appreciated, too, as I am only starting to learn scripting.

Attached you can find screenshots, the grasshopper setup with the ghpython script and the working rhino script.

Error message 1
Error message 1735Ă—1032 165 KB

Error message 2
Error message 2735Ă—1032 194 KB

gh excerpt.gh (9.5 KB)
grasshopper assembly.3dm (820.2 KB)

Thank you very much, with best regards,
Aero

Mero Script V2, test.py (2.4 KB)

2

Hello Aero,

it’s kind of hard to see what you are really trying to do. If I get you right, you are just trying to get the vectors along a line or polyline. This doesn’t need any Rhino common scripting and can be achieved simpler and easier to understand. Take a look at this script and try to continue from there:

vector_along_line.py (518 Bytes)
gh_vector_along_line.gh (11.3 KB)

1 Like
3

Thanks, Peter, for taking the time to understand the issue. You’re a genius! It is beautiful that it is this simple.
I will implement your solution later today.

Though you solved the issue, in order to understand the program better, I would still like to know why I got the error messages in my script. Can you see what caused them?

4

I didn’t invest a lot of time into the actual error message. From what I know the phyton editor in grasshopper won’t necessarily provide all the functions that the Rhino library offers. If you want to program with the python editor in grasshopper I would recommend using the rhinoscriptsyntax prior to the Rhino library.