Rhino Document Scripting (rh_run_script)

Use this for Rhino document work via rh_run_script. For Grasshopper script components, use gh_edit_script and python-boilerplate.md / csharp-boilerplate.md.

Modes

Python and C# both run through RhinoCode (Rhino.Runtime.Code) in Rhino 8. Hopper prepends the language shebang if you omit it (#! python 3 / // #! csharp).

Python pattern

import rhinoscriptsyntax as rs
import scriptcontext as sc

doc = sc.doc
ids = rs.AddCircle((0, 0, 0), 5.0)
print(ids)

• Use scriptcontext.doc for the active document.
• Use print() for values the agent should read in the tool result.

Listing / counting objects

Rhino 8 does not support doc.Objects.GetObjectList() with zero arguments. Prefer:

• rh_query_objects from the agent (short IDs, filters, countOnly) — best for Hopper workflows.
• RhinoCommon: doc.Objects.GetObjectList(Rhino.DocObjects.ObjectType.AnyObject) or iterate for obj in doc.Objects:.
• rhinoscriptsyntax: rs.ObjectsByType(rs.filter.allobjects) — not raw GetObjectList().

import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

doc = sc.doc
count = len(rs.ObjectsByType(rs.filter.allobjects))
print(f"Total objects in doc: {count}")

C# pattern

using Rhino;
using Rhino.Geometry;

var doc = RhinoDoc.ActiveDoc;
var id = doc.Objects.AddCircle(new Circle(Point3d.Origin, 5.0));
doc.Views.Redraw();
Console.WriteLine(id);

• Write the script editor body only (no class wrapper). Hopper adds // #! csharp when missing.
• Use Console.WriteLine(...) the same way Python uses print(...) — both are captured in the tool result.
• Prefer RhinoDoc.ActiveDoc (or geometry APIs that accept doc) for document work.

Command pattern

• Prefix suppressed commands with _ (e.g. _Circle).
• Chain with spaces or newlines as in the Rhino command line.

Undo

When Hopper Pi lifecycle hooks run, all rh_run_script calls in one agent turn are grouped into one Rhino Undo step (separate from Grasshopper canvas undo).

Do not use rh_run_script for

• Adding GH components, wires, sliders → gh_* tools
• Editing a GH Python/C# script node → gh_edit_script

mds/reference/rhino-script-boilerplate.md / View source on GitHub ↗