I am writing a script which eventually will sweep a profile along a path (I know it can be done with curves but…). My first step is to check if the mesh is planar as this is required for the way I have thought of doing it. I have written the script quoted below which works fine for a mesh made flat along the axes but if you try rotating it it becomes non-planar with the figures equal to about 6 decimal places but then going of after that causing it to decide they are non planar. Is this just the accuaray that blender/python works to for its coordinates and has anyone a simple idea of how to get round it (something like rounding to 6 decimal places)?

Neil.

```
import Blender
from Blender import *
from Blender.Draw import *
from math import *
path=Object.GetSelected()[0]
print "Checking object "+path.name+"..."
mesh=NMesh.GetRawFromObject(path.name)
print "Calculating normal..."
x0,y0,z0=mesh.verts[0].co
x1,y1,z1=mesh.verts[1].co
x2,y2,z2=mesh.verts[2].co
xn=abs((y1-y0)*(z2-z0)-(z1-z0)*(y2-y0))
yn=abs((z1-z0)*(x2-x0)-(x1-x0)*(z2-z0))
zn=abs((x1-x0)*(y2-y0)-(y1-y0)*(x2-x0))
ln = sqrt(xn*xn+yn*yn+zn*zn)
xn /= ln
yn /= ln
zn /= ln
print "Normal: ("+str(xn)+","+str(yn)+","+str(zn)+")"
print "Checking vertices..."
planar=-1
for a in range(2,len(mesh.verts)):
v=mesh.verts[a]
xv,yv,zv=v.co
xnv=abs((y1-y0)*(zv-z0)-(z1-z0)*(yv-y0))
ynv=abs((z1-z0)*(xv-x0)-(x1-x0)*(zv-z0))
znv=abs((x1-x0)*(yv-y0)-(y1-y0)*(xv-x0))
lnv = sqrt(xnv*xnv+ynv*ynv+znv*znv)
xnv /= lnv
ynv /= lnv
znv /= lnv
if (xnv==xn)&(ynv==yn)&(znv==zn):
print "Vertex "+str(v.index)+": OK"
else:
print "Vertex "+str(v.index)+": Non-planar!"
print xv,yv,zv
planar=0
if planar:
print "Finished: mesh is planar!"
else:
print "MESH NON-PLANAR!!!"
```