from D2104: reference all repeated (and strange) equations (example: mul_m4_m4m4(pmat_local, pmat, obmat)) in the function `precalc_project. This is useful for maintenance.
from D2104: reference all repeated (and strange) equations (example: mul_m4_m4m4(pmat_local, pmat, obmat)) in the function `precalc_project. This is useful for maintenance.