This tool derives the median surface from a selected set of surfaces and places it at the origin point of a scene. As an early version of a tool, it is interesting, but the functional value is still undetermined and very much open to suggestion.

Rhino Script

Option Explicit
'Script written by <insert name>
'Script copyrighted by <insert company name>
'Script version Monday, March 17, 2008 6:54:49 PM

Call Main()
Sub Main()
	Dim objects, object
	objects = Rhino.GetObjects("Select Surfaces", 8)
	If isNull(objects) Then Exit Sub
	Call Rhino.EnableRedraw(False)
	object = MedianObject(objects)
	Call Rhino.EnableRedraw(True)
	
End Sub
Function MedianObject(surfaces)
	MedianObject = Null
	Dim i,j,k,r,m
	Dim Ucount,Vcount,Udom,Vdom,objCount,pCount,pDom
	Dim arrU(),arrV(),domU(),domV()
	Dim tempPtSet
	Dim srfPts(),srfPtSet(),arrSrfPts(),ctrlCrvPts()
	objCount = uBound(surfaces)
	ReDim arrU(objCount), arrV(objCount),domU(objCount),domV(objCount)
	'Find out existing surface parameters
	For i = 0 To objCount Step 1
		pCount = Rhino.SurfacePointCount(surfaces(i))
		pDom = Rhino.SurfaceDegree(surfaces(i))
		arrU(i) = pCount(0)
		arrV(i) = pCount(1)
		domU(i) = pDom(0)
		domV(i) = pDom(1)
		'Call Rhino.Print(arrU(i))
		'Call Rhino.Print(arrV(i))
	Next
	'find you maximum values
	Dim surfRe, objCopy
	Udom = Rhino.Max(domU)
	Vdom = Rhino.Max(domV)
	Ucount = Rhino.Max(arrU)
	Vcount = Rhino.Max(arrV)
	
	Dim ptCount: ptCount = Ucount * Vcount - 1
	
	Dim ptX(), ptY(), ptZ(),ptXset(),ptYset(),ptZset()
	Dim srfXmin(),srfYmin(),srfZmin()
	ReDim srfPts(Vcount),srfPtSet(Ucount),arrSrfPts(objCount)
	ReDim ptX(ptCount), ptY(ptCount), ptZ(ptCount),ptXset(objCount),ptYset(objCount),ptZset(objCount)
	ReDim srfXmin(objCount),srfYmin(objCount),srfZmin(objCount)
	
	'rebuild the surfaces based on max values
	For i = 0 To objCount Step 1
		objCopy = Rhino.CopyObject(surfaces(i))
		Call Rhino.ObjectColor(objCopy, RGB(255, 0, 0))
		surfRe = Rhino.RebuildSurface(objCopy, array(Udom, Vdom), array(Ucount, Vcount))
		srfPts(i) = Rhino.SurfacePoints(objCopy)
		'extract control points
		For j = 0 To ptCount Step 1
			ptX(j) = srfPts(i)(j)(0)
			ptY(j) = srfPts(i)(j)(1)
			ptZ(j) = srfPts(i)(j)(2)
		Next
		srfXmin(i) = Rhino.Min(ptX)
		srfYmin(i) = Rhino.Min(ptY)
		srfZmin(i) = Rhino.Min(ptZ)
		'normalize the point sets
		For j = 0 To ptCount Step 1
			ptX(j) = ptX(j) - srfXmin(i)
			ptY(j) = ptY(j) - srfYmin(i)
			ptZ(j) = ptZ(j) - srfZmin(i)
		Next
		ptXset(i) = ptX
		ptYset(i) = ptY
		ptZset(i) = ptZ
		Call Rhino.DeleteObject(objCopy)
	Next
	'construct a surface at the model space centerpoint which is the median of the existing surfaces
	Dim ptMed(), ptXmed, ptYmed(), ptZmed(), ptXtemp(), ptYtemp(), ptZtemp()
	ReDim ptMed(ptCount), ptXmed(ptCount), ptYmed(ptCount), ptZmed(ptCount), ptXtemp(objCount), ptYtemp(objCount), ptZtemp(objCount)
	For i = 0 To ptCount Step 1
		For j = 0 To objCount Step 1
			ptXtemp(j) = ptXset(j)(i)
			ptYtemp(j) = ptYset(j)(i)
			ptZtemp(j) = ptZset(j)(i)
		Next
		ptXmed(i) = Rhino.Sum(ptXtemp) / (objCount + 1)
		ptYmed(i) = Rhino.Sum(ptYtemp) / (objCount + 1)
		ptZmed(i) = Rhino.Sum(ptZtemp) / (objCount + 1)
		
		ptMed(i) = array(ptXmed(i), ptYmed(i), ptZmed(i))
	Next
	Dim endSurf
	endSurf = Rhino.AddSrfControlPtGrid(array(Ucount, Vcount), ptMed, array(Udom, Vdom))
	
	
	MedianObject = endSurf
End Function