box b1 10 10 10
box b2 5 0 0 10 10 10

# fuse boxes
bfuse r b1 b2

# save Fuse history
savehistory fuse_hist

# simplify result
unifysamedom ru r

# save USD history
savehistory usd_hist


# check modifications of the faces of the boxes in two histories
explode b1 f
explode b2 f

foreach i {3 4 5 6} {
  if {[regexp "The shape has not been modified." [modified m1 fuse_hist b1_$i]]} {
    puts "Error: Incorrect history of Fuse";
    continue;
  }
  checknbshapes m1 -face 2

  if {[regexp "The shape has not been modified." [modified m2 fuse_hist b2_$i]]} {
    puts "Error: Incorrect history of Fuse";
    continue;
  }
  checknbshapes m2 -face 2

  # each face of the m1 and m2 should have been modified into the same face during USD

  compound usd_face

  foreach f [join [list [explode m1 f] [explode m2 f] ] ] {
    if {[regexp "The shape has not been modified." [modified u usd_hist $f]]} {
      puts "Error: Incorrect history of USD";
      continue;
    }
    checknbshapes u -vertex 4 -edge 4 -wire 1 -face 1
    checkprops u -s 150
    add u usd_face
  }

  checknbshapes usd_face -face 1
  checkprops u -s 150 -skip
  
}