function Curves()
	'declare variables					
	dim C1,C2,C3,C4				'curves
	dim C1pt,C2pt,C3pt,C4pt			'series of positions along C1 and C2
	dim C1pt1,C1pt2,C1pt3,C1pt4		'actual points on C1 and C2
	dim C2pt1,C2pt2,C2pt3,C2pt4
	dim C3pt1,C3pt2,C3pt3,C3pt4
	dim C4pt1,C4pt2,C4pt3,C4pt4
	dim C1ptset
	dim C2ptset
	dim C3ptset
	dim C4ptset
	
	C1pt1=array(0,0,0)
	C1pt2=array(-3,20,2)
	C1pt3=array(0,40,1)
	C1pt4=array(2,60,0)
	C1ptset=array(C1pt1,C1pt2,C1pt3,C1pt4)	'complete set of points on C1
	
	C2pt1=array(5,0,27)
	C2pt2=array(1,20,25)
	C2pt3=array(2,40,20)
	C2pt4=array(4,60,15)
	C2ptset=array(C2pt1,C2pt2,C2pt3,C2pt4)	'complete set of points on C2
	
	C3pt1=array(0.5,0,0)
	C3pt2=array(0,20,2)
	C3pt3=array(5,40,1)
	C3pt4=array(2.5,60,0)
	C3ptset=array(C3pt1,C3pt2,C3pt3,C3pt4)

	C4pt1=array(5.5,0,27)
	C4pt2=array(4,20,25)
	C4pt3=array(3,40,20)
	C4pt4=array(4.5,60,15)
	C4ptset=array(C4pt1,C4pt2,C4pt3,C4pt4)
	
	C1=rhino.addinterpcurve(C1ptset) 'creating C1
	C2=rhino.addinterpcurve(C2ptset) 'creating C2
	C3=rhino.addinterpcurve(C3ptset)
	C4=rhino.addinterpcurve(C4ptset)
	 	
	
	call ribs(C1,C2,C3,C4)	'executing ribs	
end function

'curves

'create ribs between C1 and C2
function ribs(a,b,c,d)			'set ribs variable to a,b, for later substition of C1,C2

dim ribcurves		'declare ribcurves
dim riblines		'declare stright ribs
dim i				'declare range
dim param1,param2,param3,param4	'parameteres for curve domain
dim Uval1,Uval2,Uval3,Uval4		'Umin and Umax
dim pset1,pset2,psets1,psets2		'series of positions on C1 and C2 and C3 (mid points)
redim pset3(2)
redim pset4(2)
dim path			'extrusion path
dim subdiv			'number of subdivisions
subdiv=10
redim ribsCrvset(subdiv)
redim riblineset(subdiv)


for i=0 to subdiv		'i ranges from 0 to subdiv
	param1=rhino.curveDomain(a)		'param1 chooses curve domain, in this case C1
	param2=rhino.curveDomain(b)		'param2 chooses curve domain, in this case C2
	Uval1=((param1(1)-param1(0))/subdiv)*i	'determine subdivisions on UV scale on C1
	Uval2=((param2(1)-param2(0))/subdiv)*i	'determine subdivisions on UV scale on C2
	pset1=rhino.evaluateCurve(a,Uval1)		'mapping subdivisions (Uval1) on C1
	pset2=rhino.evaluateCurve(b,Uval2)		'mapping subdivisions (Uval2) on C2
	
	
	pset3(0)=(pset1(0)-(2*(subdiv-i)))	'x-coordinates of all mid points (C3) are adjusted
	pset3(1)=(pset1(1))					'y-coordinates of all mid points (C3) are adjusted
	pset3(2)=(pset1(2)+pset2(2))/2		'z-coordinates of all mid points (C3) are adjusted
	
	pset4(0)=pset3(0)+0.5
	pset4(1)=pset3(1)
	pset4(2)=pset3(2)
	
	ribcurves=rhino.addcurve(array(pset1,pset3,pset2))	'produce rib curves
	ribsCrvset(i)=ribcurves	
	path=rhino.addline(pset3,pset4)
	call rhino.extrudecurve(ribcurves,path)
	
	
	param3=rhino.curveDomain(c)
	param4=rhino.curveDomain(d)
	Uval3=((param3(1)-param3(0))/subdiv)*i	'determine subdivisions on UV scale on straight rib 1
	Uval4=((param4(1)-param4(0))/subdiv)*i	'determine subdivisions on UV scale on straight rib 2
	psets1=rhino.evaluatecurve(c,Uval3)
	psets2=rhino.evaluatecurve(d,Uval4)
	
	riblines=rhino.addline(psets1,psets2)
	riblineset(i)=riblines
	call rhino.extrudecurve(riblines,path)
	
	
next	'next set of rib curves
	
	'create positions on surface
	dim S1								'declare S1 as lofted surface
	S1=rhino.addloftsrf(ribscrvset)
	dim S2
	S2=rhino.addloftsrf(riblineset)
	dim j									'declare j range
	dim paramu,paramv						'declare parameters on u and v directions for surface domain
	dim arrparam(1)							'declare Uvals and Vvals for subdivion	
	dim arrpoint							'get a set of points on the surface in both U and V directions
	dim psetuv
	
	rhino.print "this is the limit: "+cstr(limit)
	dim limit
	limit=10									'limit number
	redim clpoints(limit,limit)							
	
	for j=0 to limit
		for k=0 to limit					'range of j
		paramu=rhino.surfacedomain(S1(0),0)	'set up paramu within S1
		paramv=rhino.surfacedomain(S1(0),1)	'set up paramv
		arrparam(0)=paramu(0)+(((paramu(1)-paramu(0))/limit)*j)	'map out a series of U values along u direction of S1
		arrparam(1)=paramv(0)+(((paramv(1)-paramv(0))/limit)*k)	'map out a serie sof V values along v direction of S1
		arrpoint=rhino.evaluatesurface(S1(0),arrparam)	
	
		psetuv=rhino.addpoints(arrpoint) 'check to see if positions are successfully obtained
		
		clpoints(j,k)=arrpoint			'important:psetuv returns a string, which is not usable when an array is required.
		next
		
	next
	
	dim arrsrf								'declare group of surfaces
	redim S3(limit-1,limit-1)				'single surface S3
			
	for j=0 to limit-1						'declare range for j, with limit-1 in order not to go out of range
		for k=0 to limit-1					'declare range for k, with limit-1 in order not to go out of range
	
		arrsrf=Rhino.AddSrfPt (array(clpoints(j,k),clpoints(j,k+1),clpoints(j+1,k+1),clpoints(1+j,k)))		'create group of surfaces by specifying points on S1. clpoints is a group 
		S3(j,k)=arrsrf						'store S3 in arrsrf
		next
	next
	
	
	

	
	dim IsoCrv												'declare isocurve
	dim arrparameter
	dim isoparam(1)											'declare isoparam: a set of uv values that are different from arrparam
	redim isoCrvset(limit)
	dim path2
	path2=rhino.addline(pset4,pset3)
	
	for k=0 to limit
		 isoparam(0)=paramu(0)+(paramu(1)-paramu(0))		'u value of isoparam
		 isoparam(1)=paramv(0)+(((paramv(1)-paramv(0))/limit)*k)		'v value of isoparam
		 isopoint=rhino.evaluatesurface(S1(0),isoparam)	
		 rhino.print rhino.pt2str(isopoint)
		 arrparameter=rhino.surfaceclosestpoint(S1(0),isopoint)
		 rhino.command "_selcrv _hide"
		 IsoCrv=Rhino.ExtractIsocurve(S1(0),arrparameter,0)	'extract isocurve
		 isoCrvset(k)=isocrv
		 call rhino.extrudecurve(isocrv(0),path2)
		 rhino.print "this is the limit "+cstr(limit)
	next
	
		
		
	    call rhino.deleteobject(path)
	    call rhino.deleteobject(path2)
	    call rhino.deleteobject(s1(0))
	    
end function
	
	
curves