Binary STL File Reader in Python Powered by Numpy

At the STL and Fortran post Don Durschmidt asked if the stl binary reader fortran code can be made faster for reading big files.

As Abraham Maslow said “To a man with a hammer, everything looks like a nail” Likewise to an Engineer smitten by python, everything is pythonable.

So while exploring and thinking about the problem, I wrote this python version of STL binary file reader powered by numpy. Haven’t check the speed, I am sure its going to fail the speed test compared to fortran code but having a python version opens up whole new possibilities to play with the data. I think Don will agree.

Now back to the fortran binary stl file reader.

# -*- coding: utf-8 -*-
"""
Created on Thu Nov 19 06:37:35 2013

@author: Sukhbinder Singh

Reads a Binary file and 
Returns Header,Points,Normals,Vertex1,Vertex2,Vertex3

"""
import numpy as np
from struct import unpack

def BinarySTL(fname):
    fp = open(fname, 'rb')
    Header = fp.read(80)
    nn = fp.read(4)
    Numtri = unpack('i', nn)[0]
    #print nn
    record_dtype = np.dtype([
                   ('normals', np.float32,(3,)),  
                   ('Vertex1', np.float32,(3,)),
                   ('Vertex2', np.float32,(3,)),
                   ('Vertex3', np.float32,(3,)) ,              
                   ('atttr', '<i2',(1,) )
    ])
    data = np.fromfile(fp , dtype = record_dtype , count =Numtri)
    fp.close()

    Normals = data['normals']
    Vertex1= data['Vertex1']
    Vertex2= data['Vertex2']
    Vertex3= data['Vertex3']

    p = np.append(Vertex1,Vertex2,axis=0)
    p = np.append(p,Vertex3,axis=0) #list(v1)
    Points =np.array(list(set(tuple(p1) for p1 in p)))
    
    return Header,Points,Normals,Vertex1,Vertex2,Vertex3
 
if __name__ == '__main__':
    fname = "ship.stl" # "porsche.stl"
    head,p,n,v1,v2,v3 = BinarySTL(fname)
    print head
    print p.shape

Get from github