Solvespace Binary STL export to ASCII STL

Solvespace 零件檔案轉出 Binary STL 格式, 利用下列 Python 程式轉為 Binary STL 格式後, 轉進 Range3 系統中.

import struct
normals = []
points = []
triangles = []
triangle_number = 0
def load_binary_stl(fp):
    '''
    二位元 STL 檔案格式如下:
    檔案標頭共有 80 個字元(bytes), 內容通常省略, 但是內容不可使用 solid, 以免與文字檔案 STL 混淆
    UINT8[80] – Header
    UINT32 – Number of triangles (I:佔 4 bytes 的 unsigned integer)
 
    foreach triangle
    REAL32[3] – Normal vector (f:每一座標分量為一佔 4 bytes 的 float, 共佔 12 bytes)
    REAL32[3] – Vertex 1
    REAL32[3] – Vertex 2
    REAL32[3] – Vertex 3
    UINT16 – Attribute byte count (H:兩個 bytes 的 unsigned short, 表示 attribute byte count)
    end
 
    '''
    # 已經在外部開檔
    #fp=open(filename,'rb')
    header=fp.read(80)
    triangle_number = struct.unpack('I',fp.read(4))[0]
    #print(triangle_number)
    count=0
    while True:
        try:
            p=fp.read(12)
            if len(p)==12:
                n=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                normals.append(n)
                l = len(points)
                #print(n)
            p=fp.read(12)
            if len(p)==12:
                p1=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                points.append(p1)
                #print(p1)
            p=fp.read(12)
            if len(p)==12:
                p2=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                points.append(p2)
            p=fp.read(12)
            if len(p)==12:
                p3=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                points.append(p3)
                triangles.append((l, l+1, l+2))
            # 使用 count 來計算三角形平面個數
            # triangle_number 為 STL 檔案中的三角形個數
            count += 1
            #print(count)
            # 在前面 12*4 個 bytes 的 normal 與三個點資料後, 為
            # 一個 2 bytes 長的 unsigned short, 其值為零, 為 attribute
            fp.read(2)
            # 讀完所有三角平面後, 即跳出 while
            if count > triangle_number:
                break
        except EOFError:
            break
    #fp.close()
def read_length(f):
    length = struct.unpack("@i", f.read(4))
    return length[0]
def read_header(f):
    f.seek(f.tell()+80)
def write_as_ascii(outfilename):
    f = open(outfilename, "w")
    f.write ("solid "+outfilename+"\n")
    for n  in range(len(triangles)):
        f.write ("facet normal {} {} {}\n".format(normals[n][0],normals[n][1],normals[n][2]))
        f.write ("outer loop\n")
        f.write ("vertex {} {} {}\n".format(points[triangles[n][0]][0],points[triangles[n][0]][1],points[triangles[n][0]][2]))
        f.write ("vertex {} {} {}\n".format(points[triangles[n][1]][0],points[triangles[n][1]][1],points[triangles[n][1]][2]))
        f.write ("vertex {} {} {}\n".format(points[triangles[n][2]][0],points[triangles[n][2]][1],points[triangles[n][2]][2]))
        f.write ("endloop\n")
        f.write ("endfacet\n")
    f.write ("endsolid "+outfilename+"\n")
    f.close()
def main():
    infilename = "binary1.stl"
    outfilename = "ascii1.stl"
    try:
        f = open(infilename, "rb")
        #read_header(f)
        #l = read_length(f)
        try:
            load_binary_stl(f)
            l = len(normals)
        except Exception as e:
            print("Exception",e)
        print(len(normals), len(points), len(triangles), l)
        write_as_ascii(outfilename)
        print("done")
    except Exception as e:
        print(e)
if __name__ == '__main__':
    main()

其他相關程式:

建立 Binary STL 零件檔案:

#coding: utf-8
import struct
 
class StLFacet:
    def __init__(self, normal, v1, v2, v3, att_bc=0):
        self.coords = [normal, v1, v2, v3]
        self.att_bc = att_bc
 
class StL:
    def __init__(self, header):
        self.header = header
        self.facets = []
    def add_facet(self, facet):
        self.facets.append(facet)
    def get_binary(self):
        # 原先 2.0 的版本
        #out = ['%-80.80s' % self.header]
        # 改為 Python 3.0 格式
        # 第一行標頭的格式
        header = ['%-80.80s' % self.header][0]
        # 利用 bytes() 將標頭字串轉為二位元資料
        out = [bytes(header,encoding="utf-8")]
        # 接著則計算三角形面的數量, 並以二位元長整數格式存檔
        out.append(struct.pack('L',len(self.facets)))
        # 接著則依照法線向量與三個點座標的格式, 分別以浮點數格式進行資料附加
        for f in self.facets:
            for coord in f.coords:
                out.append(struct.pack('3f', *coord))
            # att_bc 則內定為 0
            out.append(struct.pack('H', f.att_bc))
        return b"".join(out)
 
def test():
    stl=StL('Header ...')
    stl.add_facet(StLFacet((0.,0.,1.),(0.,0.,0.),(1.,0.,0.),(0.,1.,0.)))
    stl.add_facet(StLFacet((0.,0.,1.),(1.,0.,0.),(1.,1.,0.),(0.,1.,0.)))
    # 第二個平面
    stl.add_facet(StLFacet((0.,-1.,0.),(0.,0.,0.),(0.,0.,-1.),(1.,0.,-1.)))
    stl.add_facet(StLFacet((0.,-1.,0.),(0.,0.,0.),(1.,0.,-1.),(1.,0.,0.)))
    return stl.get_binary()
 
# 指定存為 binary 格式檔案
stlfile = open("test.stl", "wb")
stlcontent = test()
stlfile.write(stlcontent)

PyGame STL viewer:

#coding: utf-8
# STL viewer 原始檔案來自
# University of Wuppertal - http://mbi-wiki.uni-wuppertal.de/wordpress/
# Modified by Uli Eggersmann
# Binary STL 資料讀取原始作者 Oliver Marks - http://www.linux.com
# 原始檔案僅讀取 Text STL 零件檔案
# 2011 Fall 由 KMOL 新增 Binary STL 零件檔案讀取
 
from visual import scene, color, materials, faces, points
import os, struct
 
#file ="ritzel.stl"
 
file ="binary.stl"
 
scene.width = 400
scene.height = 400
scene.background = color.white # black
# 視窗標題取自 cvisual.pyd, 不可使用中文
scene.title = "STLViewer in VPython"
 
print ("利用滑鼠右鍵旋轉")
print ("滑鼠左右鍵同時按下後移動, 可以縮放畫面")
 
# Read STL file, only use vertex-line with xyz coordinates
list = []
 
#load stl file detects if the file is a text file or binary file
def load_stl(filename):
    #read start of file to determine if its a binay stl file or a ascii stl file
    fp=open(filename,'rb')
    header=fp.read(80)
    filetype=header[0:5]
    # 這裡必須要能夠分辨二位元字串與文字字串
    #print (type(filetype))
    #print (filetype)
    fp.close()
 
    # for Python 3
    if filetype==b'solid':
    # for Python 2
    #if filetype=='solid':
        print ("讀取文字檔案格式:"+str(filename))
        load_text_stl(filename)
    else:
        print ("讀取二位元檔案格式:"+str(filename,))
        load_binary_stl(filename)
 
#load binary stl file check wikipedia for the binary layout of the file
#we use the struct library to read in and convert binary data into a format we can use
def load_binary_stl(filename):
    '''
    二位元 STL 檔案格式如下:
    檔案標頭共有 80 個字元(bytes), 內容通常省略, 但是內容不可使用 solid, 以免與文字檔案 STL 混淆
    UINT8[80] – Header
    UINT32 – Number of triangles (I:佔 4 bytes 的 unsigned integer)
 
    foreach triangle
    REAL32[3] – Normal vector (f:每一座標分量為一佔 4 bytes 的 float, 共佔 12 bytes)
    REAL32[3] – Vertex 1
    REAL32[3] – Vertex 2
    REAL32[3] – Vertex 3
    UINT16 – Attribute byte count (H:兩個 bytes 的 unsigned short, 表示 attribute byte count)
    end
 
    '''
    global list
 
    fp=open(filename,'rb')
    header=fp.read(80)
 
    triangle_number = struct.unpack('I',fp.read(4))[0]
    count=0
    while True:
        try:
            p=fp.read(12)
            if len(p)==12:
                n=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
 
            p=fp.read(12)
            if len(p)==12:
                p1=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                list.append(p1)
            p=fp.read(12)
            if len(p)==12:
                p2=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                list.append(p2)
            p=fp.read(12)
            if len(p)==12:
                p3=[struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]]
                list.append(p3)
            # 使用 count 來計算三角形平面個數
            # triangle_number 為 STL 檔案中的三角形個數
            count += 1
            # 在前面 12*4 個 bytes 的 normal 與三個點資料後, 為
            # 一個 2 bytes 長的 unsigned short, 其值為零, 為 attribute
            fp.read(2)
            # 讀完所有三角平面後, 即跳出 while
            if count > triangle_number:
                break
        except EOFError:
            break
    fp.close()
 
 
def load_text_stl(filename):
    global list
    for dataline in open(filename,"r").readlines():
        if not dataline.strip(): # skip blank lines
            continue
        field = dataline.split() # split with no argument makes the right place!
        if field[0] == "vertex":
            list.append([float(x) for x in field[1:4]])
            #print (list)
            #break
            #for x in field[1:4]:
                #print(x)
 
load_stl(os.path.abspath('')+'/'+file)
 
 
# Graphics
model = faces(pos=list, color=(0.8,0.8,0.8),
              material=materials.plastic) # creates triangles
# 請注意, 這裡並沒有使用 STL 檔案中的平面 normal, 而是利用 VPython make_normals() 產生
model.make_normals() # creates plane normals
model.smooth(0.93) # smooths the edges
# = AllepunkteSTL points (pos = list, size = 3, color = Color.Black) # generates points 

PyGame 與 OpenGL 檢視 STL

#coding: utf8
# source: https://www.linux.com/community/blogs/133-general-linux/291889
import os
import struct
 
from OpenGL.GL import *
from OpenGL.GLU import *
import pygame
from pygame.locals import *
 
#class for a 3d point
class createpoint:
    def __init__(self,p,c=(1,0,0)):
        self.point_size=0.5
        self.color=c
        self.x=p[0]
        self.y=p[1]
        self.z=p[2]
 
    def glvertex(self):
        glVertex3f(self.x,self.y,self.z)
 
#class for a 3d face on a model
class createtriangle:
    points=None
    normal=None
 
    def __init__(self,p1,p2,p3,n=None):
        #3 points of the triangle
        self.points=createpoint(p1),createpoint(p2),createpoint(p3)
 
        #triangles normal
        self.normal=createpoint(self.calculate_normal(self.points[0],self.points[1],self.points[2]))#(0,1,0)#
 
    #calculate vector / edge
    def calculate_vector(self,p1,p2):
        return -p1.x+p2.x,-p1.y+p2.y,-p1.z+p2.z
 
    def calculate_normal(self,p1,p2,p3):
        a=self.calculate_vector(p3,p2)
        b=self.calculate_vector(p3,p1)
        #calculate the cross product returns a vector
        return self.cross_product(a,b)    
 
    def cross_product(self,p1,p2):
        return (p1[1]*p2[2]-p2[1]*p1[2]) , (p1[2]*p2[0])-(p2[2]*p1[0]) , (p1[0]*p2[1])-(p2[0]*p1[1])
 
class loader:
    model=[]
 
    #return the faces of the triangles
    def get_triangles(self):
        if self.model:
            for face in self.model:
                yield face
 
    #draw the models faces
    def draw(self):
        glBegin(GL_TRIANGLES)
        for tri in self.get_triangles():
            glNormal3f(tri.normal.x,tri.normal.y,tri.normal.z)
            glVertex3f(tri.points[0].x,tri.points[0].y,tri.points[0].z)
            glVertex3f(tri.points[1].x,tri.points[1].y,tri.points[1].z)
            glVertex3f(tri.points[2].x,tri.points[2].y,tri.points[2].z)
        glEnd()
 
    #load stl file detects if the file is a text file or binary file
    def load_stl(self,filename):
        #read start of file to determine if its a binay stl file or a ascii stl file
        fp=open(filename,'rb')
        h=fp.read(80)
        type=h[0:5]
        fp.close()
 
        if type=='solid':
            print ("reading text file"+str(filename))
            self.load_text_stl(filename)
        else:
            print ("reading binary stl file "+str(filename,))
            self.load_binary_stl(filename)
 
    #read text stl match keywords to grab the points to build the model
    def load_text_stl(self,filename):
        fp=open(filename,'r')
 
        for line in fp.readlines():
            words=line.split()
            if len(words)>0:
                if words[0]=='solid':
                    self.name=words[1]
 
                if words[0]=='facet':
                    center=[0.0,0.0,0.0]
                    triangle=[]
                    normal=(eval(words[2]),eval(words[3]),eval(words[4]))
 
                if words[0]=='vertex':
                    triangle.append((eval(words[1]),eval(words[2]),eval(words[3])))
 
 
                if words[0]=='endloop':
                    #make sure we got the correct number of values before storing
                    if len(triangle)==3:
                        self.model.append(createtriangle(triangle[0],triangle[1],triangle[2],normal))
        fp.close()
 
    #load binary stl file check wikipedia for the binary layout of the file
    #we use the struct library to read in and convert binary data into a format we can use
    def load_binary_stl(self,filename):
        fp=open(filename,'rb')
        h=fp.read(80)
 
        l=struct.unpack('I',fp.read(4))[0]
        count=0
        while True:
            try:
                p=fp.read(12)
                if len(p)==12:
                    n=struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]
 
                p=fp.read(12)
                if len(p)==12:
                    p1=struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]
 
                p=fp.read(12)
                if len(p)==12:
                    p2=struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]
 
                p=fp.read(12)
                if len(p)==12:
                    p3=struct.unpack('f',p[0:4])[0],struct.unpack('f',p[4:8])[0],struct.unpack('f',p[8:12])[0]
 
                new_tri=(n,p1,p2,p3)
 
                if len(new_tri)==4:
                    tri=createtriangle(p1,p2,p3,n)
                    self.model.append(tri)
                count+=1
                fp.read(2)
 
                if len(p)==0:
                    break
            except EOFError:
                break
        fp.close()
 
 
 
class draw_scene:
    def __init__(self,style=1):
        #create a model instance and
        self.model1=loader()
        #self.model1.load_stl(os.path.abspath('')+'/text.stl')
        self.model1.load_stl(os.path.abspath('')+'/cube.stl')
        self.init_shading()
 
 
    #solid model with a light / shading
    def init_shading(self):
        glShadeModel(GL_SMOOTH)
        glClearColor(0.0, 0.0, 0.0, 0.0)
        glClearDepth(1.0)
        glEnable(GL_DEPTH_TEST)
        glShadeModel(GL_SMOOTH) 
        glDepthFunc(GL_LEQUAL)
        glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)
 
        glEnable(GL_COLOR_MATERIAL)
        glEnable(GL_LIGHTING)
        glEnable(GL_LIGHT0)   
        glLight(GL_LIGHT0, GL_POSITION,  (0, 1, 1, 0))      
        glMatrixMode(GL_MODELVIEW)
 
    def resize(self, width, height):
        if height==0:
            height=1
        glViewport(0, 0, width, height)
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        gluPerspective(45, 1.0*width/height, 0.1, 100.0)
        #gluLookAt(0.0,0.0,45.0,0,0,0,0,40.0,0)
        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()
 
 
    def init(self):
        glShadeModel(GL_SMOOTH)
        glClearColor(0.0, 0.0, 0.0, 0.0)
        glClearDepth(1.0)
        glEnable(GL_DEPTH_TEST)
        glShadeModel(GL_SMOOTH) 
        glDepthFunc(GL_LEQUAL)
        glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)
 
 
        glEnable(GL_COLOR_MATERIAL)
 
        glEnable(GL_LIGHTING)
        glEnable(GL_LIGHT0)   
        glLight(GL_LIGHT0, GL_POSITION,  (0, 1, 1, 0))
 
        glMatrixMode(GL_MODELVIEW)
 
    def draw(self):
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
        glLoadIdentity()
 
        glTranslatef(0.0,-26.0, -100.0)
        self.model1.draw()
 
#main program loop
def main():
    #initalize pygame
    pygame.init()
    pygame.display.set_mode((640,480), OPENGL|DOUBLEBUF)
 
    #setup the open gl scene
    scene=draw_scene()
    scene.resize(640,480)
 
    frames = 0
    ticks = pygame.time.get_ticks()
    while 1:
        event = pygame.event.poll()
        if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):
            break
 
        #draw the scene
        scene.draw()
        pygame.display.flip()
        frames = frames+1
 
    print ("fps:  %d" % ((frames*1000)/(pygame.time.get_ticks()-ticks)))
 
if __name__ == '__main__':
    main()

另一個 STL Writer:

#coding:utf-8
# source: http://code.activestate.com/recipes/578246-stl-writer/
 
import struct
 
ASCII_FACET = """facet normal 0 0 0
outer loop
vertex {face[0][0]:.4f} {face[0][1]:.4f} {face[0][2]:.4f}
vertex {face[1][0]:.4f} {face[1][1]:.4f} {face[1][2]:.4f}
vertex {face[2][0]:.4f} {face[2][1]:.4f} {face[2][2]:.4f}
endloop
endfacet
"""
 
BINARY_HEADER ="80sI"
BINARY_FACET = "12fH"
 
class ASCII_STL_Writer:
    """ Export 3D objects build of 3 or 4 vertices as ASCII STL file.
    """
    def __init__(self, stream):
        self.fp = stream
        self._write_header()
 
    def _write_header(self):
        self.fp.write("solid python\n")
 
    def close(self):
        self.fp.write("endsolid python\n")
 
    def _write(self, face):
        self.fp.write(ASCII_FACET.format(face=face))
 
    def _split(self, face):
        p1, p2, p3, p4 = face
        return (p1, p2, p3), (p3, p4, p1)
 
    def add_face(self, face):
        """ Add one face with 3 or 4 vertices. """
        if len(face) == 4:
            face1, face2 = self._split(face)
            self._write(face1)
            self._write(face2)
        elif len(face) == 3:
            self._write(face)
        else:
            raise ValueError('only 3 or 4 vertices for each face')
 
    def add_faces(self, faces):
        """ Add many faces. """
        for face in faces:
            self.add_face(face)
 
class Binary_STL_Writer(ASCII_STL_Writer):
    """ Export 3D objects build of 3 or 4 vertices as binary STL file.
    """
    def __init__(self, stream):
        self.counter = 0
        super(Binary_STL_Writer, self).__init__(stream)
 
    def close(self):
        self._write_header()
 
    def _write_header(self):
        self.fp.seek(0)
        self.fp.write(struct.pack(BINARY_HEADER, b'Python Binary STL Writer', self.counter))
 
    def _write(self, face):
        self.counter += 1
        data = [
            0., 0., 0.,
            face[0][0], face[0][1], face[0][2],
            face[1][0], face[1][1], face[1][2],
            face[2][0], face[2][1], face[2][2],
            0
        ]
        self.fp.write(struct.pack(BINARY_FACET, *data))
 
 
def example():
    def get_cube():
        # cube corner points
        s = 3.
        p1 = (0, 0, 0)
        p2 = (0, 0, s)
        p3 = (0, s, 0)
        p4 = (0, s, s)
        p5 = (s, 0, 0)
        p6 = (s, 0, s)
        p7 = (s, s, 0)
        p8 = (s, s, s)
 
        # define the 6 cube faces
        # faces just lists of 3 or 4 vertices
        return [
            [p1, p5, p7, p3],
            [p1, p5, p6, p2],
            [p5, p7, p8, p6],
            [p7, p8, p4, p3],
            [p1, p3, p4, p2],
            [p2, p6, p8, p4],
        ]
    '''
    for writing ASCII STL cube file
    with open('cube_ascii.stl', 'w') as fp:
        writer = ASCII_STL_Writer(fp)
        writer.add_faces(get_cube())
        writer.close()
    '''
    with open('cube_bin.stl', 'wb') as fp:
        writer = Binary_STL_Writer(fp)
        writer.add_faces(get_cube())
        writer.close()
 
if __name__ == '__main__':
    example()