cylinder surf 1 
trimv surf surf -10 10
plane pp 0 0 0 1 0 1
intersect ii surf pp 
extsurf surf ii 0 0 1
trimv surf surf -1 1
convert surf surf
mkface f surf
getanasurf asurf f cyl  1.e-7
if {[isdraw asurf]} {
  set log [dump asurf]
  if { [regexp {CylindricalSurface} $log ] != 1 } {
     puts "Error: surface is not a cylindrical surface"
  }
} else {
  puts "Error: required surface is not got"
}

