Preface

Discusses how to define a plane equation within MineSight® Grail. Specifically how to define a plane equation for use in the grail.data.geometry module.

Defining the Plane Equation

The plane equation within MineSight® Grail is typically referred to via a four float tuple. The four float tuples refer to the equation for a plane, where each element in the tuple corresponds to the coefficients of the actual equation,

Ax+By+Cz+D=0

The coefficients in the tuple are represented as,

(A, B, C, D,)

The A, B, and C define the direction of the normal to the plane. So for a typical Plan view, where we want each plane to be horizontal, the normal would point in the Z direction. Now D specifies the "height" for the plane equation. However, in the plane equation that is used in the grail.data.msr module the height is really -D. Therefore, we need to negate D when we are specifying the plane equation. Thus to get a plane of 2015.0, we would specify the coefficients to be,

(0, 0, 1, -2015.0)

That would correspond to a plane equation of,

0x+0y+1z-2015.0 = 0
       0x+0y+1z = 2015.0
              z = 2015.0

More complex planes can be described by shifting the A, B, and C values such to create a normal to the desired plane.