// general purpose facet-drop which calls xy_normal_length(), normal_length(),
// and center_height() on the subclass
bool MillingCutter::facetDrop(CLPoint &cl, const Triangle &t) const { // Drop cutter at (cl.x, cl.y) against facet of Triangle t
Point normal = t.upNormal(); // facet surface normal
if ( isZero_tol( normal.z ) ) // vertical surface
return false; //can't drop against vertical surface
assert( isPositive( normal.z ) );
if ( ( isZero_tol(normal.x) ) && ( isZero_tol(normal.y) ) ) { // horizontal plane special case
CCPoint cc_tmp( cl.x, cl.y, t.p[0].z, FACET);
return cl.liftZ_if_inFacet(cc_tmp.z, cc_tmp, t);
} else { // general case
// plane containing facet: a*x + b*y + c*z + d = 0, so
// d = -a*x - b*y - c*z, where (a,b,c) = surface normal
double d = - normal.dot(t.p[0]);
normal.normalize(); // make length of normal == 1.0
Point xyNormal( normal.x, normal.y, 0.0);
xyNormal.xyNormalize();
// define the radiusvector which points from the cc-point to the cutter-center
Point radiusvector = this->xy_normal_length*xyNormal + this->normal_length*normal;
CCPoint cc_tmp = cl - radiusvector; // NOTE xy-coords right, z-coord is not.
cc_tmp.z = (1.0/normal.z)*(-d-normal.x*cc_tmp.x-normal.y*cc_tmp.y); // cc-point lies in the plane.
cc_tmp.type = FACET;
double tip_z = cc_tmp.z + radiusvector.z - this->center_height;
return cl.liftZ_if_inFacet(tip_z, cc_tmp, t);
}
}
// because this checks for contact with both the tip and the circular edge it is hard to move to the base-class
// we either hit the tip, when the slope of the plane is smaller than angle
// or when the slope is steep, the circular edge between the cone and the cylindrical shaft
bool ConeCutter::facetDrop(CLPoint &cl, const Triangle &t) const {
bool result = false;
Point normal = t.upNormal(); // facet surface normal
if ( isZero_tol( normal.z ) ) // vertical surface
return false; //can't drop against vertical surface
if ( (isZero_tol(normal.x)) && (isZero_tol(normal.y)) ) { // horizontal plane special case
CCPoint cc_tmp( cl.x, cl.y, t.p[0].z, FACET_TIP ); // so any vertex is at the correct height
return cl.liftZ_if_inFacet(cc_tmp.z, cc_tmp, t);
} else {
// define plane containing facet
// a*x + b*y + c*z + d = 0, so
// d = -a*x - b*y - c*z, where (a,b,c) = surface normal
double a = normal.x;
double b = normal.y;
double c = normal.z;
double d = - normal.dot(t.p[0]);
normal.xyNormalize(); // make xy length of normal == 1.0
// cylindrical contact point case
// find the xy-coordinates of the cc-point
CCPoint cyl_cc_tmp = cl - radius*normal;
cyl_cc_tmp.z = (1.0/c)*(-d-a*cyl_cc_tmp.x-b*cyl_cc_tmp.y);
double cyl_cl_z = cyl_cc_tmp.z - length; // tip positioned here
cyl_cc_tmp.type = FACET_CYL;
// tip contact with facet
CCPoint tip_cc_tmp(cl.x,cl.y,0.0);
tip_cc_tmp.z = (1.0/c)*(-d-a*tip_cc_tmp.x-b*tip_cc_tmp.y);
double tip_cl_z = tip_cc_tmp.z;
tip_cc_tmp.type = FACET_TIP;
result = result || cl.liftZ_if_inFacet( tip_cl_z, tip_cc_tmp, t);
result = result || cl.liftZ_if_inFacet( cyl_cl_z, cyl_cc_tmp, t);
return result;
}
}
