Box.Contains(Point) == true is not true

[RIL (Rolf)]

@Terry_Chappell

Rolf,

Do you now have code for correctly determining if point is inside box?

I’ve been using Radovan Grmusa’s (@RadovanG) very fast cylinder inclusion test also for boxes.

Super-super fast Point Inclusion test for Cylinder/Breps?

I put together some code which: is based purely on geometry and algebra and does not create instances of Point3D or Vector3D types uses just pure double types in computing so it is supposed to be fast All explanation about alghorithm is embended in the code as comments. On my PC ( Intel® Xeon® Processor E3-1241 v3 3.50 GHz, 16GB RAM, Win10 Pro) speed of execution for 47.000 points is not mesurable in milliseconds (0 miliseconds). With 500.000 of points time execution becomes 5-6 m…

The way I used it was by defining three center axes (and a cylinder enclosing the box in that direction) and testing for each axis/cylinder, and skipping (break) the first time a point isn’t inside the cylinder.

Unfortunately my final code is a bit “involved” and entangled in a library I had planned to adapt to GPU processing, but in Radovan’s cylinder test is in the link, and well documented. Just nest the axes/cylinder tests to break early, somethiong along these lines:

bool PointInsideBox(Point3d pt, Vector3d axis1, Vector3d axis2, Vector3d axis3)
{
    if not PointInsideCylinder(pt, axis1) return false;
    if not PointInsideCylinder(pt, axis2) return false;
    if not PointInsideCylinder(pt, axis3) return false;
    return true; // is inside
}

The concept looks something like this if illustrated (no rotation is needed to align axes with world, but I have not tested if that would be faster or not, all I know is that this test is quite fast):

Just a crazy idea I had, and it was fast enough for the use case I had at the time.

// Rolf