Option Explicit

'------------------------------------------------------------------------------
'Subroutine: Roof
'Purpose:    an example of parametric design
'Pablo Miranda Carranza, code released under GNU General Public License (www.gnu.org/licenses/gpl.txt)
'------------------------------------------------------------------------------

Sub Roof()
Dim strObject
Dim arrPoints
Dim arrCount
Dim u,v
Dim pt1,pt2,pt3,pt4
Dim ctrface
Dim ctrcirc
Dim uvparam
Dim tropdir
Dim normp
Dim normsize
Dim vec1,vec2
Dim d1,d2,d3,d4
Dim base1,base2,base3,base4
Dim basepts(4)
Dim toppts(4)
Dim surfacegen
Dim scval

strObject = Rhino.GetObject("Pick a surface", 8)

arrPoints = Rhino.SurfacePoints(strObject)

arrCount = Rhino.SurfacePointCount(strObject)

Rhino.Print "Point count in U direction: " & CStr(ArrCount(0))
Rhino.Print "Point count in V direction: " & CStr(ArrCount(1))

ctrface=array(0,0,0)
ctrcirc=array(0,0,0)

normp=array(0,0,0)
tropdir=array(1,0.5,-0.5)


For u = 0 To arrCount(1) - 2

For v = 0 To arrCount(0) - 2

    'these are the indexes, or the 'adresses' of the four points in each rectangular 'patch' of the surface
    pt1= u*arrCount(0)+v
    pt2= (u+1)*arrCount(0)+v
    pt3= (u+1)*arrCount(0)+v+1
    pt4= u*arrCount(0)+v+1
    
    'calculate centroid, average position of the four vertices of the surface
    ctrface(0)=arrPoints(pt1)(0)+arrPoints(pt2)(0)+arrPoints(pt3)(0)+arrPoints(pt4)(0)
    ctrface(1)=arrPoints(pt1)(1)+arrPoints(pt2)(1)+arrPoints(pt3)(1)+arrPoints(pt4)(1)
    ctrface(2)=arrPoints(pt1)(2)+arrPoints(pt2)(2)+arrPoints(pt3)(2)+arrPoints(pt4)(2)
    
    ctrface(0)=ctrface(0)/4
    ctrface(1)=ctrface(1)/4
    ctrface(2)=ctrface(2)/4


     'calculate normal. Since we are using the control points, this won't exactly be the normal to the surface...
     vec1=array(arrPoints(pt2)(0)-arrPoints(pt1)(0),arrPoints(pt2)(1)-arrPoints(pt1)(1),arrPoints(pt2)(2)-arrPoints(pt1)(2))
     vec2=array(arrPoints(pt3)(0)-arrPoints(pt1)(0),arrPoints(pt3)(1)-arrPoints(pt1)(1),arrPoints(pt3)(2)-arrPoints(pt1)(2))
     

     normp(0) = vec1(1)*vec2(2) - vec1(2)*vec2(1)
     normp(1) = vec1(2)*vec2(0) - vec1(0)*vec2(2)
     normp(2) = vec1(0)*vec2(1) - vec1(1)*vec2(0)
     
     normsize=sqr(normp(0)*normp(0)+ normp(1)*normp(1)+normp(2)*normp(2))
     
     normp(0)=normp(0)/normsize
     normp(1)=normp(1)/normsize
     normp(2)=normp(2)/normsize

    'and now put the circle, its centre in the centre of the square (calculated above)
    'and a normal direction added, to give some distance from it

    ctrcirc(0)=ctrface(0)- normp(0)
    ctrcirc(1)=ctrface(1)- normp(1)
    ctrcirc(2)=ctrface(2)- normp(2)

    d1= array(arrPoints(pt1)(0)-ctrface(0),arrPoints(pt1)(1)-ctrface(1),arrPoints(pt1)(2)-ctrface(2))
    d2= array(arrPoints(pt2)(0)-ctrface(0),arrPoints(pt2)(1)-ctrface(1),arrPoints(pt2)(2)-ctrface(2))
    d3= array(arrPoints(pt3)(0)-ctrface(0),arrPoints(pt3)(1)-ctrface(1),arrPoints(pt3)(2)-ctrface(2))
    d4= array(arrPoints(pt4)(0)-ctrface(0),arrPoints(pt4)(1)-ctrface(1),arrPoints(pt4)(2)-ctrface(2))


     basepts(0)=arrPoints(pt4)
     basepts(1)=arrPoints(pt3)
     basepts(2)=arrPoints(pt2)
     basepts(3)=arrPoints(pt1)
     basepts(4)=arrPoints(pt4)

     base1=Rhino.AddCurve (basepts ,1)
     
     ctrcirc(0)=ctrface(0)- 2*normp(0)+0.5*tropdir(0)
     ctrcirc(1)=ctrface(1)- 2*normp(1)+0.5*tropdir(1)
     ctrcirc(2)=ctrface(2)- 2*normp(2)+0.5*tropdir(2)

     scval=0.6
     basepts(0)=array(ctrcirc(0)+scval*d3(0),ctrcirc(1)+scval*d3(1),ctrcirc(2)+scval*d3(2))
     basepts(1)=array(ctrcirc(0)+scval*d4(0),ctrcirc(1)+scval*d4(1),ctrcirc(2)+scval*d4(2))
     basepts(2)=array(ctrcirc(0)+scval*d1(0),ctrcirc(1)+scval*d1(1),ctrcirc(2)+scval*d1(2))
     basepts(3)=array(ctrcirc(0)+scval*d2(0),ctrcirc(1)+scval*d2(1),ctrcirc(2)+scval*d2(2))
     basepts(4)=array(ctrcirc(0)+scval*d3(0),ctrcirc(1)+scval*d3(1),ctrcirc(2)+scval*d3(2))
     
     base2=Rhino.AddCurve (basepts ,3)

     ctrcirc(0)=ctrcirc(0)- normp(0)+tropdir(0)
     ctrcirc(1)=ctrcirc(1)- normp(1)+tropdir(1)
     ctrcirc(2)=ctrcirc(2)- normp(2)+tropdir(2)

     scval=0.4
     basepts(0)=array(ctrcirc(0)+scval*d1(0),ctrcirc(1)+scval*d1(1),ctrcirc(2)+scval*d1(2))
     basepts(1)=array(ctrcirc(0)+scval*d4(0),ctrcirc(1)+scval*d4(1),ctrcirc(2)+scval*d4(2))
     basepts(2)=array(ctrcirc(0)+scval*d3(0),ctrcirc(1)+scval*d3(1),ctrcirc(2)+scval*d3(2))
     basepts(3)=array(ctrcirc(0)+scval*d2(0),ctrcirc(1)+scval*d2(1),ctrcirc(2)+scval*d2(2))
     basepts(4)=array(ctrcirc(0)+scval*d1(0),ctrcirc(1)+scval*d1(1),ctrcirc(2)+scval*d1(2))
     
     base3=Rhino.AddCurve (basepts ,3)


    Rhino.command ("-loft selID " & base1 & " selID " &  base2 & " selID " &  base3 & " enter enter enter")





  Next

Next

End Sub


Roof()