I assume this one's right. If you say so, I will add it to the wiki's "code snippets" section, for future reference.
public float[] getWorldSpaceBounds() {
float[] objectSpaceBounds = terrain.getMesh().getBoundingBox();
SimpleVector mins = new SimpleVector(objectSpaceBounds[0], objectSpaceBounds[2], objectSpaceBounds[4]);
SimpleVector maxs = new SimpleVector(objectSpaceBounds[1], objectSpaceBounds[3], objectSpaceBounds[5]);
SimpleVector[] p = new SimpleVector[8];
p[0] = new SimpleVector(mins.x, mins.y, maxs.z); p[1] = new SimpleVector(mins.x, mins.y, mins.z); p[2] = new SimpleVector(maxs.x, mins.y, mins.z);
p[3] = new SimpleVector(maxs.x, mins.y, maxs.z); p[4] = new SimpleVector(maxs.x, maxs.y, mins.z);
p[5] = new SimpleVector(maxs.x, maxs.y, maxs.z); p[6] = new SimpleVector(mins.x, maxs.y, mins.z); p[7] = new SimpleVector(mins.x, maxs.x, maxs.z);
float minX = Float.MAX_VALUE, minY = Float.MAX_VALUE, minZ = Float.MAX_VALUE, maxX = Float.MIN_VALUE, maxY = Float.MIN_VALUE, maxZ = Float.MIN_VALUE;
for (int i = 0; i < 8; i++) {
p[i].matMul(terrain.getWorldTransformation());
if (p[i].x < minX)
minX = p[i].x;
if (p[i].y < minY)
minY = p[i].y;
if (p[i].z < minZ)
minZ = p[i].z;
if (p[i].x > maxX)
maxX = p[i].x;
if (p[i].y > maxY)
maxY = p[i].y;
if (p[i].z > maxZ)
maxZ = p[i].z;
}
float[] worldSpaceBounds = new float[6];
worldSpaceBounds[0] = minX;
worldSpaceBounds[2] = minY;
worldSpaceBounds[4] = minZ;
worldSpaceBounds[1] = maxX;
worldSpaceBounds[3] = maxY;
worldSpaceBounds[5] = maxZ;
return worldSpaceBounds;
}