How to read the normal vector

From: Wanchai Rattanawong (
Date: Mon Jul 26 1999 - 08:46:11 EEST

Dear RP's List

I try to analyse the facet normal vector from the STL format. This is the example
that I exported the file from CAD system to STL file.

solid Untitled1
  facet normal 9.86393923E-01 1.64398991E-01 0.00000000E+00
    outer loop
      vertex 9.73762280E-01 7.40301994E-01 1.35078953E+00
      vertex 1.00078931E+00 5.78139828E-01 1.35078953E+00
      vertex 1.00078931E+00 5.78139828E-01 3.50789527E-01

 The result that I determined from this example, it is not match to the facet normal
from the STL file. Anyone know how to analyse the facet normal vector, please let

Thank in advance,
Wanchai Rattanawong
Industrial Research Institute Swinburne (IRIS)
P.O. BOX 218, Hawthorn
Victoria 3122, Australia
Tel:(613)9214 5654 Fax:(613) 9214 5050

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