sk2ldraw.py

#!/usr/bin/env python3

import ROOT

def readSK(fname, batch=False):
    global nt
    nt = ROOT.TNtuple('nt', 'nt', 'ch:pe:t:x:y:z')
    nt.ReadFile(fname)
    if not batch:
        nt.SetMarkerStyle(20)
        nt.SetMarkerSize(0.5)
        nt.Draw("z:y:x:pe", "", "col")
        return

    maxpe = nt.GetMaximum('pe')

    for i in range(nt.GetEntries()):
        nt.GetEntry(i)
        # LDraw axes (+X, +Z, -Y)
        pe, x, z, y = nt.pe, nt.x, nt.y, -nt.z
        # LDR colors
        # https://www.ldraw.org/article/547.html
        colors = [33, 44, 36, 38, 54, 46, 47]
        ncolors = len(colors)
        color = colors[int(pe / (maxpe * 1.001 / ncolors))]
        shape = '4073.dat'
        rot = ROOT.TRotation()

        if y == -1810: # top
            rot.RotateZ(ROOT.TMath.Pi())
        elif y == 1810: # bottom
            pass # keep upward
        else: # side
            rot.RotateZ(-ROOT.TMath.Pi() / 2)
            rot.RotateY(-ROOT.TMath.ATan2(z, x))

        Rxx, Rxy, Rxz = rot.XX(), rot.XY(), rot.XZ()
        Ryx, Ryy, Ryz = rot.YX(), rot.YY(), rot.YZ()
        Rzx, Rzy, Rzz = rot.ZX(), rot.ZY(), rot.ZZ()

        print('1 %d %f %f %f %f %f %f %f %f %f %f %f %f %s' % (color, x / 3, y / 3, z / 3, Rxx, Rxy, Rxz, Ryx, Ryy, Ryz, Rzx, Rzy, Rzz, shape))        

if __name__ == '__main__':
    import sys
    readSK(sys.argv[1], True)