When we start the new model, we found many problems, an especially problem about Gap bonnet, after we assemble upper and side Bonnets.In many times, we try to find out the root cause, but we don't have any actual curve because drawing is provided only dimension. We cannot prove that Bonnet curve is in standard drawing. We don't have any tool for actual curve bonnet checking and show that they are correct or not. Then, we solve problem slowly