puts "========"
puts "0031437: Offset surface throws e x c e p t i o n when trying to evaluate at singularity point"
puts "========"
puts ""

restore [locate_data_file bug31437.draw] s

set dist 2.5
offset result s -$dist

svalue s 0 1 x1 y1 z1
svalue result 0 1 x2 y2 z2

set curDist2 [expr ([dval x1] - [dval x2])**2 + ([dval y1] - [dval y2])**2 + ([dval z1] - [dval z2])**2]
if {abs($curDist2 - $dist**2) < 1.e-7} {
  puts "OK: offset correct"
} else {
  puts "Error: offset is wrong"
}

checkview -display result -2d -path ${imagedir}/${test_image}.png