SetLineLength.py

import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

def SetLineLength():
    
    def line_filter( rhino_object, geometry, component_index):
        if geometry.IsLinear():
            return True
        return False
    looped = False
    while True:
        length = 1
        if sc.sticky.has_key('LINE_EX_LENGTH'):
            length = sc.sticky['LINE_EX_LENGTH']
        go = Rhino.Input.Custom.GetObject()
        strMessage = "Pick the end of the line to move."
        if looped: strMessage = "Pick the end of the line to move. Press enter to finish."
        go.SetCommandPrompt(strMessage)
        go.GeometryFilter = Rhino.DocObjects.ObjectType.Curve
        go.SetCustomGeometryFilter(line_filter)
        opLen = Rhino.Input.Custom.OptionDouble(length)
        go.AddOptionDouble("Length", opLen)
        go.AcceptNumber(True, False)
        go.EnablePreSelect(False, True)
        rc = go.Get()
        
        if go.CommandResult() != Rhino.Commands.Result.Success:
            return go.CommandResult()
            
        if rc == Rhino.Input.GetResult.Option:
            length = opLen.CurrentValue
            sc.sticky['LINE_EX_LENGTH'] = length
            continue
            
        if rc == Rhino.Input.GetResult.Number:
            length = go.Number()
            sc.sticky['LINE_EX_LENGTH'] = length
            continue
            
        if rc == Rhino.Input.GetResult.Object:
            objref = go.Object(0)
            geo = objref.Geometry()
            selPt = objref.SelectionPoint()
            
            p_rc, par = geo.ClosestPoint(selPt)
            if p_rc:
                if par>= geo.Domain.Mid:
                    vec = geo.PointAtEnd-geo.PointAtStart
                    vec.Unitize()
                    geo.SetEndPoint(geo.PointAtStart + vec*length)
                else:
                    
                    vec = geo.PointAtStart-geo.PointAtEnd
                    vec.Unitize()
                    geo.SetStartPoint(geo.PointAtEnd + vec*length)
                    
                sc.doc.Objects.Replace (objref, geo)
                print "Line length set to " + str(round(length, 3))
                looped = True
                sc.doc.Views.Redraw()
            continue
    
if __name__ == '__main__':SetLineLength()