miscellaneous-scad

from loadmesh import loadMesh
from sys import argv, stderr

def toSCAD(polygons,name="stlObject1"):
    def format(v):
        return '[%.7g,%.7g,%.7g]' % tuple(v)

    scad = []
    scad.append(name + '_points=[')
    
    minDimension = min( max(max(v[i] for v in polygon) for polygon in polygons) - 
        min(min(v[i] for v in polygon) for polygon in polygons) for i in range(3))
        
    def fix3(v):
        return tuple(x if abs(x) > 1e-7 * minDimension else 0. for x in v)
    
    stderr.write("Getting points.\n" )
    pointDict = {}
    points = []
    m = [float("inf"),float("inf"),float("inf")]
    M = [float("-inf"),float("-inf"),float("-inf")]
    for polygon in polygons:
        for v in polygon:
            vv = fix3(v)
            for i in range(3):
                m[i] = min(m[i],vv[i])
                M[i] = max(M[i],vv[i])
            
    sizes = [M[i]-m[i] for i in range(3)]
    m[0] = .5*(m[0]+M[0]) # center x

    for polygon in polygons:
        for v in polygon:
            vv = fix3(v)
            s = format(vv[i]-m[i] for i in range(3))
            if s not in pointDict:
                pointDict[s] = len(pointDict)
                scad.append('   '+s+",")

    scad.append(' ];')
    scad.append(name + '_faces=[')
    stderr.write("Getting faces.\n" )
    for polygon in polygons:
        p = '  ['
        for v in polygon:
            vv = fix3(v)
            s = format(vv[i]-m[i] for i in range(3))
            p += '%d,' % pointDict[s]
        scad.append(p+'],')
    scad.append('];')
    scad.append('module ' + name + '() { polyhedron(points=' + name + '_points, faces=' + name + '_faces); }')
    scad.append(name+"_min=[for(i=[0:2]) min([for(p=" + name + "_points) p[i]])];")
    scad.append(name+"_max=[for(i=[0:2]) max([for(p=" + name + "_points) p[i]])];")
    scad.append(name+'_size=[for(i=[0:2]) '+name+'_max[i]-'+name+'_min[i]];')
    scad.append(name+'();')
    stderr.write("Joining.\n" )
    return '\n'.join(scad)
    
if __name__ == '__main__':
    objectName = argv[2] if len(argv) > 2 else "stlObject1";
    print(toSCAD(loadMesh(argv[1], reverseTriangles=True), name=objectName))