// a function for displaying the normals in an STL file
public static void draw_stl_normals(GLWindow g, STLSurf s)
{
// draw triangle normas
foreach (Geo.Tri t in s.tris)
{
// from STL file
Geo.Point p1 = new Geo.Point(t.p[0].x, t.p[0].y, t.p[0].z);
Geo.Point p2 = new Geo.Point(t.p[0].x + t.n.x, t.p[0].y + t.n.y, t.p[0].z + t.n.z);
GeoLine l = new GeoLine(p1, p2);
l.color = System.Drawing.Color.Green;
g.addGeom(l);
// calculate yourself:
Vector v1 = new Vector(t.p[0].x - t.p[1].x, t.p[0].y - t.p[1].y, t.p[0].z - t.p[1].z);
Vector v2 = new Vector(t.p[0].x - t.p[2].x, t.p[0].y - t.p[2].y, t.p[0].z - t.p[2].z);
Vector n;
n = v1.Cross(v2); // the normal is in the direction of the cross product between the edge vectors
n = (1 / n.Length()) * n; // normalize to length==1
p1 = new Geo.Point(t.p[0].x, t.p[0].y, t.p[0].z);
p2 = new Geo.Point(t.p[0].x + n.x, t.p[0].y + n.y, t.p[0].z + n.z);
l = new GeoLine(p1, p2);
l.color = System.Drawing.Color.Blue;
g.addGeom(l);
}
}
public double Dot(Vector v)
{
// dot product
return x * v.x + y * v.y + z * v.z;
}
public Vector Cross(Vector v)
{
// cross product
// NEEDS TESTING!
double xc = y * v.z - z * v.y;
double yc = z * v.x - x * v.z;
double zc = x * v.y - y * v.x;
return new Vector(xc, yc, zc);
}
public void recalc_normals()
{
// normal data from STL files is usually junk, so recalculate:
Vector v1 = new Vector(p[0].x - p[1].x, p[0].y - p[1].y, p[0].z - p[1].z);
Vector v2 = new Vector(p[0].x - p[2].x, p[0].y - p[2].y, p[0].z- p[2].z);
n = v1.Cross(v2); // the normal is in the direction of the cross product between the edge vectors
n = (1 / n.Length()) * n; // normalize to length==1
}
public Tri(Vector N)
{
// a strange constructor indeed...
p = new Point[3];
bb = new Bbox();
p[0] = new Point();
p[1] = new Point();
p[2] = new Point();
n = N;
}
public Tri(Point P1, Point P2, Point P3, Vector N)
{
p = new Point[3];
bb = new Bbox();
p[0] = P1;
p[1] = P2;
p[2] = P3;
n = N;
}
public Tri(Point P1, Point P2, Point P3)
{
p = new Point[3];
bb = new Bbox();
p[0] = P1;
p[1] = P2;
p[2] = P3;
// if normal is not given, calculate it here.
Vector v1 = new Vector(p[0].x - p[1].x, p[0].y - p[1].y, p[0].z - p[1].z);
Vector v2 = new Vector(p[0].x - p[2].x, p[0].y - p[2].y, p[0].z- p[2].z);
n = v1.Cross(v2); // the normal is in the direction of the cross product between the edge vectors
n = (1 / n.Length()) * n; // normalize to length==1
}
public static double? FacetTest(Cutter cu, Point e, Tri t)
{
// local copy of the surface normal
t.recalc_normals(); // don't trust the pre-calculated normal! calculate it separately here.
Vector n = new Vector(t.n.x, t.n.y, t.n.z);
Point cc;
if (n.z == 0)
{
// vertical plane, can't touch cutter against that!
return null;
}
else if (n.z < 0)
{
// flip the normal so it points up (? is this always required?)
n = -1*n;
}
// define plane containing facet
double a = n.x;
double b = n.y;
double c = n.z;
double d = - n.x * t.p[0].x - n.y * t.p[0].y - n.z * t.p[0].z;
// the z-direction normal is a special case (?required?)
// in debug phase, see if this is a useful case!
if ((a == 0) && (b == 0))
{
// System.Console.WriteLine("facet-test:z-dir normal case!");
e.z = t.p[0].z;
cc = new Point(e.x,e.y,e.z);
if (isinside(t, cc))
{
// System.Console.WriteLine("facet-test:z-dir normal case!, returning {0}",e.z);
// System.Console.ReadKey();
return e.z;
}
else
return null;
}
// System.Console.WriteLine("facet-test:general case!");
// facet test general case
// uses trigonometry, so might be too slow?
// flat endmill and ballnose should be simple to do without trig
// toroidal case might require offset-ellipse idea?
/*
theta = asin(c);
zf= -d/c - (a*xe+b*ye)/c+ (R-r)/tan(theta) + r/sin(theta) -r;
e=[xe ye zf];
u=[0 0 1];
rc=e + ((R-r)*tan(theta)+r)*u - ((R-r)/cos(theta) + r)*n;
t=isinside(p1,p2,p3,rc);
*/
double theta = Math.Asin(c);
double zf = -d/c - (a*e.x+b*e.y)/c + (cu.R-cu.r)/Math.Tan(theta) + cu.r/Math.Sin(theta) - cu.r;
Vector ve = new Vector(e.x,e.y,zf);
Vector u = new Vector(0,0,1);
Vector rc = new Vector();
rc = ve +((cu.R-cu.r)*Math.Tan(theta)+cu.r)*u - ((cu.R-cu.r)/Math.Cos(theta)+cu.r)*n;
/*
if (rc.z > 1000)
System.Console.WriteLine("z>1000 !");
*/
cc = new Point(rc.x, rc.y, rc.z);
// check that CC lies in plane:
// a*rc(1)+b*rc(2)+c*rc(3)+d
double test = a * cc.x + b * cc.y + c * cc.z + d;
if (test > 0.000001)
System.Console.WriteLine("FacetTest ERROR! CC point not in plane");
if (isinside(t, cc))
{
if (Math.Abs(zf) > 100)
{
System.Console.WriteLine("serious problem... at" +e.x + "," + e.y);
}
return zf;
}
else
return null;
}
public Tri()
{
p = new Point[3];
bb = new Bbox();
p[0] = new Point(0,0,0);
p[1] = new Point(0, 0, 0);
p[2] = new Point(0, 0, 0);
n = null;
}
public static STLSurf Load(System.IO.StreamReader fs)
{
// Here's where autodetection will be provided for loading binary stl files and by wrapping STLA(scii) and STLB(inary)
// but for now as only one format is provided, not bothering with it, we need to define a object format for handling file loading/saving
// System.IO.StreamReader fs = new System.IO.StreamReader(FileName);
STLSurf surf = new STLSurf();
int state = 0;
int counter = 0;
string[] data;
Geo.Tri triangle = new Geo.Tri();
Vector normal = new Vector();
System.Globalization.CultureInfo locale = new System.Globalization.CultureInfo("en-GB");
int n_triangles=0;
while ( !fs.EndOfStream ) {
data = fs.ReadLine().TrimStart(' ').Split(' ');
switch (state)
{
case 0:
if (data[0].Equals("solid"))
{
surf.name = data[1];
state = 1; // continue readingx
}
break;
case 1:
if (data[0].Equals("facet")) {
normal.x = double.Parse(data[2], locale);
normal.y = double.Parse(data[3], locale);
normal.z = double.Parse(data[4], locale);
triangle = new Geo.Tri(normal);
counter = 0;
state = 2;
}
break;
case 2:
if (data[0].Equals("vertex"))
{
if ( counter <= 2 ) {
triangle.p[counter].x = double.Parse(data[1], locale);
triangle.p[counter].y = double.Parse(data[2], locale);
triangle.p[counter].z = double.Parse(data[3], locale);
// System.Console.WriteLine("STLReader: added point" + triangle.p[counter]);
// System.Console.ReadKey();
counter++;
}
} else if (data[0].Equals("endfacet"))
{
if (counter == 3)
{
surf.AddTriangle(triangle);
n_triangles += 1;
}
state = 1;
}
break;
}
}
fs.Close();
System.Console.WriteLine("STLReader: read {0} triangles!",n_triangles);
return (surf);
}
public static STLSurf Load(System.IO.StreamReader fs)
{
STLSurf surf = new STLSurf();
int state = 0;
int counter = 0;
string[] data;
Tri triangle = new Tri();
Vector normal = new Vector();
System.Globalization.CultureInfo locale = new System.Globalization.CultureInfo("en-GB");
int n_triangles=0;
while ( !fs.EndOfStream ) {
data = fs.ReadLine().TrimStart(' ').Split(' ');
switch (state)
{
case 0:
if (data[0].Equals("solid"))
{
state = 1; // continue readingx
}
break;
case 1:
if (data[0].Equals("facet")) {
normal.x = double.Parse(data[2], locale);
normal.y = double.Parse(data[3], locale);
normal.z = double.Parse(data[4], locale);
triangle = new Tri(normal);
counter = 0;
state = 2;
}
break;
case 2:
if (data[0].Equals("vertex"))
{
if ( counter <= 2 ) {
triangle.p[counter].x = double.Parse(data[1], locale);
triangle.p[counter].y = double.Parse(data[2], locale);
triangle.p[counter].z = double.Parse(data[3], locale);
// System.Console.WriteLine("STLReader: added point" + triangle.p[counter]);
// System.Console.ReadKey();
counter++;
}
} else if (data[0].Equals("endfacet"))
{
if (counter == 3)
{
surf.AddTriangle(triangle);
n_triangles += 1;
}
state = 1;
}
break;
}
}
fs.Close();
System.Console.WriteLine("STLReader: read {0} triangles!",n_triangles);
return (surf);
}
