MichLet file generator from Kayak Foundry export

kfoundry2michlet.fsx

open System
open System.IO

let cSs = File.ReadAllLines(@"C:\Extras\kfoundry1.6.4\520x50a.txt")
(* 
    Raw form data exported from kfoundry with baseline at the waterline looks like this:

    Form Position, X (mm), Y (mm)
    ...
    Form at 52 cm, 60, 39.3333
    Form at 52 cm, 54.6667, 25
    Form at 52 cm, 49, 11.6667
    Form at 52 cm, 43, 0
    Form at 52 cm, 36.6667, -10
    Form at 52 cm, 33.3333, -14.6667
    Form at 52 cm, 29.6667, -18.6667
    Form at 52 cm, 28, -20.6667
    ...

    Michlet only takes shape data for the below the waterline - so we only want the negative portion.
    Michlet uses constant vertical intervals... so we need to treat y like x and interpolate a value for x

*)

let rawForms =
    cSs
    |> Seq.skip 1
    |> Seq.filter (fun l -> not(l.StartsWith("Cockpit") ) )
    |> Seq.filter (fun l -> not(l.StartsWith("Bow") ) )
    |> Seq.filter (fun l -> not(l.StartsWith("Stern") ) )
    |> Seq.filter ( String.IsNullOrEmpty >> not )

let parseRawForm (s:string) =
    let values = s.Replace("0,", "0.").Replace(",", "").Split(' ' )
    // and change to metres
    (float values.[2])/100., (float values.[4])/1000., (float values.[5])/1000.

let forms = 
    rawForms 
    |> Seq.map parseRawForm
    // z is Form Postion, the x and y are reversed from the file header
    |> Seq.filter ( fun (_,_,y) -> y <= 0.)
    |> Seq.groupBy ( fun (z, _, _) -> z)
    |> Seq.map (fun (z,zxy) -> (z, zxy |> Seq.map (fun (z,x,y) -> (-1. * y, x) ) |> Seq.sortBy (fun (y, _) -> y ) ) ) // changed to a function of height

let inline interpolateY xys x =
    let rec getX1Y1X2Y2' xys x =
        //printfn "list: %A" xys
        match xys with
        | (_, _)::[] -> 0.
        | [] -> 0. // if not found then michlet expects a 0 - also, that typed 0 is negating the benefit of the inline...
        | (x1, y1)::t -> 
                    let (x2, y2) = t.Head
                    if (x1 <= x) && (x < x2) then
                        //printfn "%A adjacent points: %A" x (x1, y1, x2, y2)
                        y1 + ( (y2 - y1) / (x2 - x1) * ( x - x1) )
                    else
                        getX1Y1X2Y2' t x
    getX1Y1X2Y2' xys x

let _,maxX = forms |> Seq.map (fun (z, xys) -> z, xys |> Seq.maxBy (fun (x,_) -> x) |> fun (x,_) -> x ) |> Seq.maxBy (fun (z, x) -> x)

let divs = 10.

let xVals = [0. .. maxX/divs .. maxX ]

// for each station
// iterate through xs getting the intepolated ys - straight lines good enough after all chines can be discontinuous
// write out ys - one line per station
forms
|> Seq.iter ( fun (z, xys) -> 
                            let interpolatedValues =
                                xVals 
                                |> Seq.map (fun xv -> sprintf "%.4f" (interpolateY (Seq.toList xys) xv ) )
                                |> Seq.toList
                                |> List.rev
                            //printfn "%A - %A - %s" z (Seq.toList xys) ( String.Join(",", interpolatedValues) )
                            printfn "%s" ( String.Join(",", interpolatedValues) )
            )

OK, gives the right interpolated offsets now...