F11p	1+mean(d(u,X))
F12p	mean(d(u,Y))
F13p	mean(d(u,Z))
F21p	mean(d(v,X))
F22p	1+mean(d(v,Y))
F23p	mean(d(v,Z))
F31p	mean(d(w,X))
F32p	mean(d(w,Y))
F33p	1+mean(d(w,Z))
CF11	F22p*F33p-F23p*F32p
CF12	F23p*F31p-F21p*F33p
CF13	F21p*F32p-F22p*F31p
CF21	F32p*F13p-F33p*F12p
CF22	F33p*F11p-F31p*F13p
CF23	F31p*F12p-F32p*F11p
CF31	F12p*F23p-F13p*F22p
CF32	F13p*F21p-F11p*F23p
CF33	F11p*F22p-F12p*F21p
JF	F11p*CF11+F12p*CF12+F13p*CF13
CN1	-(CF11*X+CF12*Y+CF13*Z)/a
CN2	-(CF21*X+CF22*Y+CF23*Z)/a
CN3	-(CF31*X+CF32*Y+CF33*Z)/a
Js	sqrt(CN1^2+CN2^2+CN3^2)
ns1	CN1/Js
ns2	CN2/Js
ns3	CN3/Js
Vfree	-ic((X+u)*CN1+(Y+v)*CN2+(Z+w)*CN3)/3
Rfree	(3*Vfree/(4*pi))^(1/3)
Afree	ic(Js)