Andrea Sanna Paolo Montuschi An efficient algorithm for ray casting of CSG animation frames. 229-242 1998 9 Journal of Visualization and Computer Animation 4 db/journals/jvca/jvca9.html#SannaM98 http://dx.doi.org/10.1002/(SICI)1099-1778(1998100)9:4<229::AID-VIS188>3.0.CO;2-T