//! Computes the mass properties of the p3d_polyhedre and fills the appropriate fields inside its structure.
void gpCompute_mass_properties(p3d_polyhedre *poly)
{
if(poly==NULL)
{
printf("%s: %d: gpCompute_mass_properties(): input p3d_polyhedre* is NULL.\n",__FILE__,__LINE__);
return;
}
Mass_properties mass_prop;
VOLINT_POLYHEDRON *p= NULL;
p= (VOLINT_POLYHEDRON *) malloc(sizeof(VOLINT_POLYHEDRON));
readPolyhedron(poly, p);
compMassProperties(p, &mass_prop);
poly->cmass[0]= mass_prop.r[0];
poly->cmass[1]= mass_prop.r[1];
poly->cmass[2]= mass_prop.r[2];
poly->inertia_axes[0][0]= mass_prop.J[0][0];
poly->inertia_axes[0][1]= mass_prop.J[0][1];
poly->inertia_axes[0][2]= mass_prop.J[0][2];
poly->inertia_axes[1][0]= mass_prop.J[1][0];
poly->inertia_axes[1][1]= mass_prop.J[1][1];
poly->inertia_axes[1][2]= mass_prop.J[1][2];
poly->inertia_axes[2][0]= mass_prop.J[2][0];
poly->inertia_axes[2][1]= mass_prop.J[2][1];
poly->inertia_axes[2][2]= mass_prop.J[2][2];
poly->volume= mass_prop.volume;
free(p);
}
int main(int argc, char *argv[])
{
POLYHEDRON p;
double density, mass;
double r[3]; /* center of mass */
double J[3][3]; /* inertia tensor */
if (argc != 2) {
printf("usage: %s <polyhedron geometry filename>\n", argv[0]);
exit(0);
}
readPolyhedron(argv[1], &p);
compVolumeIntegrals(&p);
printf("\nT1 = %+20.6f\n\n", T0);
printf("Tx = %+20.6f\n", T1[X]);
printf("Ty = %+20.6f\n", T1[Y]);
printf("Tz = %+20.6f\n\n", T1[Z]);
printf("Txx = %+20.6f\n", T2[X]);
printf("Tyy = %+20.6f\n", T2[Y]);
printf("Tzz = %+20.6f\n\n", T2[Z]);
printf("Txy = %+20.6f\n", TP[X]);
printf("Tyz = %+20.6f\n", TP[Y]);
printf("Tzx = %+20.6f\n\n", TP[Z]);
density = 1.0; /* assume unit density */
mass = density * T0;
/* compute center of mass */
r[X] = T1[X] / T0;
r[Y] = T1[Y] / T0;
r[Z] = T1[Z] / T0;
/* compute inertia tensor */
J[X][X] = density * (T2[Y] + T2[Z]);
J[Y][Y] = density * (T2[Z] + T2[X]);
J[Z][Z] = density * (T2[X] + T2[Y]);
J[X][Y] = J[Y][X] = - density * TP[X];
J[Y][Z] = J[Z][Y] = - density * TP[Y];
J[Z][X] = J[X][Z] = - density * TP[Z];
/* translate inertia tensor to center of mass */
J[X][X] -= mass * (r[Y]*r[Y] + r[Z]*r[Z]);
J[Y][Y] -= mass * (r[Z]*r[Z] + r[X]*r[X]);
J[Z][Z] -= mass * (r[X]*r[X] + r[Y]*r[Y]);
J[X][Y] = J[Y][X] += mass * r[X] * r[Y];
J[Y][Z] = J[Z][Y] += mass * r[Y] * r[Z];
J[Z][X] = J[X][Z] += mass * r[Z] * r[X];
printf("center of mass: (%+12.6f,%+12.6f,%+12.6f)\n\n", r[X], r[Y], r[Z]);
printf("inertia tensor with origin at c.o.m. :\n");
printf("%+15.6f %+15.6f %+15.6f\n", J[X][X], J[X][Y], J[X][Z]);
printf("%+15.6f %+15.6f %+15.6f\n", J[Y][X], J[Y][Y], J[Y][Z]);
printf("%+15.6f %+15.6f %+15.6f\n\n", J[Z][X], J[Z][Y], J[Z][Z]);
}
