Rhino.Scripting.FSharp

Rhino.Scripting.FSharp is a set of useful extensions to the Rhino.Scripting library. This includes type extension for pretty printing of Rhino objects as well as implementations of commonly used functions in curried form for use with F#.

This library allows you to compose RhinoScript functions with pipelines:

Get started by opening the Rhino.Scripting namespaces. Opening Rhino.Scripting.FSharp will extend Rhino.Scripting and Rhino.Geometry types with additional static and member functions.

#r "RhinoCommon"
#r "nuget: Rhino.Scripting.FSharp"
open Rhino.Scripting
open Rhino.Scripting.FSharp
type rs = RhinoScriptSyntax

Now you can use the |> and |>! operator to chain RhinoScript functions together in a more F# idiomatic way. The |>! operator is part of Rhino.Scripting.FSharp library. It passes its input on as output. See definition.

rs.AddPoint( 1. , 2.,  3.)
|>! rs.setLayer "my points"
|>! rs.setUserText "id" "point123"
|>  rs.setName "123"

instead of regular RhinoScript syntax like this:

let guid = rs.AddPoint( 1. , 2.,  3.)
rs.ObjectLayer (guid, "my points")
rs.SetUserText (guid, "id", "point123")
rs.ObjectName (guid, "123")

Thread Safety

While the main Rhino Document is officially not thread safe, this library can be used from any thread. If running async this library will automatically marshal all calls that affect the UI to the main Rhino UI thread and wait for switching back till completion on UI thread. Modifying the Rhino Document from a background thread is actually OK as long as there is only one thread doing it. The main reason to use this library async is to keep the Rhino UI and Fesh scripting editor UI responsive while doing long running operations.

More Examples

Transforming Objects in Pipelines

// Move, scale, and color an object in one pipeline
objectId
|>! rs.move (Vector3d(10, 0, 0))
|>! rs.scale Point3d.Origin 1.5
|>! rs.setColor Drawing.Color.Blue
|>  rs.setLayer "Transformed"

// Batch operations on multiple objects
objectIds
|>! rs.setLayers "ProcessedObjects"
|>! rs.setColors Drawing.Color.Red

// Copy all properties from a template object to another
rs.matchAllProperties sourceId targetId

Line Operations

let ln = Line(Point3d(0,0,0), Point3d(10,0,0))

// Divide a line into equal segments
let points = ln |> Line.divide 5    // 6 points (start + 5 divisions)

// Divide by maximum segment length
let pts = ln |> Line.divideMaxLength 3.0

// Extend and shrink
let longer  = ln |> Line.extend 2.0 3.0   // extend 2 at start, 3 at end
let shorter = ln |> Line.shrink 1.0 1.0   // remove 1 from each end

// Evaluate at parameter
let midPoint = ln.EvaluateAt 0.5

// Offset parallel in XY plane
let offsetLine = ln |> Line.offsetXY 2.0

// Find intersection of two infinite lines
let intersectionPt = Line.intersectInOnePoint lineA lineB

Vector3d Extensions

let v = Vector3d(3, 4, 0)

v.Length            // 5.0
v.Unitized          // unit vector with error checking
v.Direction360InXY  // angle in degrees (0 to 360)
v.IsHorizontal      // true if Z component is near zero
Vector3d.areParallel other v       // within 0.25 degrees
Vector3d.arePerpendicular other v  // within 89.75 to 90.25 degrees
v.IsParallelTo(other, Cosine.``1.0``) // custom tolerance of 1.0 degree, see Cosine module

// Interpolation
let mid = Vector3d.lerp(vecA, vecB, 0.5)
let slerped = Vector3d.slerp(vecA, vecB, 0.5) // spherical interpolation

Point3d Extensions

// Functional point manipulation
let pt =
    startPt
    |> Point3d.withZ 100.0   // set Z coordinate
    |> Point3d.moveX 10.0    // shift in X
    |> Point3d.moveY 5.0     // shift in Y

// Interpolation
let midPt = Point3d.lerp(ptA, ptB, 0.5)

// Point at a given distance toward another point
let ptAtDist = Point3d.distPt(fromPt, towardPt, 15.0)

// Distance queries
let dist = pt.DistanceTo(otherPt)
let closestOnLn = pt.ClosestPointOnLine(lnFrom, lnTo)

Plane Operations

// Create from three points
let plane = Plane.createThreePoints origin ptOnXAxis ptOnPlane

// Evaluate in plane coordinates
let pt3d = plane.EvaluateAt(2.0, 3.0, 0.0)

// Find where a line pierces a plane
match Plane.intersectLine myLine myPlane with
| Some pt -> printfn "Intersection at %A" pt
| None    -> printfn "Line is parallel to plane"

// Find the line of intersection between two planes
match Plane.intersect planeA planeB with
| Some ln -> printfn "Intersection line: %A" ln
| None    -> printfn "Planes are parallel"

Offset Polylines

// Offset a polyline with uniform distance
let offsetPts = rs.OffsetPoints(cornerPoints, 2.0, loop = true)

// Variable offset per segment
let offsetPts2 =
    rs.OffsetPoints(
        cornerPoints,
        [2.0; 3.0; 2.5; 2.0],   // different offset per segment
        [0.5; 0.5; 0.5; 0.5],   // optional normal offset
        loop = true
    )

Fillet Polyline Corners

// Fillet specific corners with individual radii
let fillets = dict [(1, 2.0); (3, 1.5)]  // corner index -> radius
let filletedCurve = rs.FilletPolyline(fillets, polylinePoints)

Point Set Queries

open Rhino.Scripting.FSharp

// Find nearest point in a set
let nearestIdx = RhPoints.closestPointIdx testPt pointList
let nearestPt  = RhPoints.closestPoint testPt pointList

// Remove near-duplicate points
let cleaned = RhPoints.cullDuplicatePointsInSeq 0.01 noisyPoints

// Find minimum distance between two point sets
let minDist = RhPoints.minDistBetweenPointSets setA setB

Sort Line Segments into a Loop

open Rhino.Scripting.FSharp

// Order disconnected line segments (a ResizeArray<Line>) into a continuous path
RhTopology.sortToLoop (fun seg -> seg) lineSegments

// With optional reversing of individual segments (here a ResizeArray<Curve>)
RhTopology.sortToLoopWithReversing
    (fun (crv:Curve) -> Line(crv.PointAtStart, crv.PointAtEnd))
    (fun idx crv -> crv.Reverse() |> ignore)
    curves

Remembered Selections

// User picks an object once; subsequent calls reuse the cached selection
let refId = rs.GetObjectAndRemember("Pick reference object")

// ... later in the script, same call returns cached result
let refId2 = rs.GetObjectAndRemember("Pick reference object")

Debugging and Visualization

// Draw a vector as an arrow in the viewport
rs.DrawVector(myVector, fromPoint, "Vectors")

// Visualize a coordinate system (draws X, Y, Z axes)
rs.DrawPlane(myPlane, 5.0, "_Base", "Guides")

Full API Documentation

goswinr.github.io/Rhino.Scripting.FSharp

Use of AI and LLMs

All core function are are written by hand to ensure performance and correctness. However, AI tools have been used for code review, typo and grammar checking in documentation and to generate not all but many of the tests.

Contributing

Contributions are welcome even for small things like typos. If you have problems with this library please submit an issue.

License

MIT

Changelog

see CHANGELOG.md