[fix-plyflatten] replaced ceil by floor
[fix-plyflatten] replaced ceil by floor

MISS3D/s2p,dyoussef/s2p,mnhrdt/s2p,MISS3D/s2p,dyoussef/s2p,jmichel-otb/s2p,jmichel-otb/s2p,MISS3D/s2p,carlodef/s2p,carlodef/s2p,mnhrdt/s2p,jmichel-otb/s2p,MISS3D/s2p,dyoussef/s2p,dyoussef/s2p,jmichel-otb/s2p