Simplify a mesh to be close to viewport preview drawing

simplified_mesh.py

# made for https://blender.stackexchange.com/q/86248/935
# duplicate a mesh to get the edges that define the shape
# skip any extra edges that are part of a flat section

import bpy
import bmesh

# source object
obj = bpy.context.object
# minimum angle between faces that will be kept.
tolerance = 0.05

src_mesh = bmesh.new()
src_mesh.from_mesh(obj.data)
flat_mesh = bmesh.new()

for e in src_mesh.edges:
    if e.calc_face_angle(200.0) > tolerance:
        v1 = flat_mesh.verts.new(e.verts[0].co)
        v2 = flat_mesh.verts.new(e.verts[1].co)
        flat_mesh.edges.new((v1,v2))

me = bpy.data.meshes.new('FlatMesh')
flat_mesh.to_mesh(me)
flat_mesh.free()
src_mesh.free()
obj = bpy.data.objects.new('FlatMesh', me)
bpy.context.scene.objects.link(obj)