# 3D Misc

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```
public class Geom3D {
// distance from point (x, y, z) to plane aX + bY + cZ + d = 0
public static double ptPlaneDist(double x, double y, double z,
double a, double b, double c, double d) {
return Math.abs(a * x + b * y + c * z + d) / Math.sqrt(a * a + b * b + c * c);
}

// distance between parallel planes aX + bY + cZ + d1 = 0 and
// aX + bY + cZ + d2 = 0
public static double planePlaneDist(double a, double b, double c,
double d1, double d2) {
return Math.abs(d1 - d2) / Math.sqrt(a * a + b * b + c * c);
}

// distance from point (px, py, pz) to line (x1, y1, z1)-(x2, y2, z2)
// (or ray, or segment; in the case of the ray, the endpoint is the
// first point)
public static final int LINE = 0;
public static final int SEGMENT = 1;
public static final int RAY = 2;

public static double ptLineDistSq(double x1, double y1, double z1,
double x2, double y2, double z2,
double px, double py, double pz,
int type) {
double pd2 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2) + (z1 - z2) * (z1 - z2);
double x, y, z;
if (pd2 == 0) {
x = x1;
y = y1;
z = z1;
} else {
double u = ((px - x1) * (x2 - x1) + (py - y1) * (y2 - y1) +
(pz - z1) * (z2 - z1)) / pd2;
x = x1 + u * (x2 - x1);
y = y1 + u * (y2 - y1);
z = z1 + u * (z2 - z1);
if (type != LINE && u < 0) {
x = x1;
y = y1;
z = z1;
}
if (type == SEGMENT && u > 1.0) {
x = x2;
y = y2;
z = z2;
}
}
return (x - px) * (x - px) + (y - py) * (y - py) + (z - pz) * (z - pz);
}

public static double ptLineDist(double x1, double y1, double z1,
double x2, double y2, double z2,
double px, double py, double pz,
int type) {
return Math.sqrt(ptLineDistSq(x1, y1, z1, x2, y2, z2, px, py, pz, type));
}
}
```