RhinoCommon C# Plane equation

The C# Plane constructor with four double arguments (API link) states it “Constructs a plane from an equation ax+by+cz=d.” However, it appears to actually construct a plane for ax+by+cz+d=0, reversing the sign of d. Is this a mistake in the documentation?

I am attaching a grasshopper script that constructs a plane with a=0, b=0, c=1, d=h, which should give a plane z=h (h is adjustable). Instead, as the elevation (h) is increased, the plane is lowered, consistent with z+h=0.

PlaneEquation.3dm (50.9 KB)
PlaneEquation.gh (2.7 KB)

The Plane.GetPlaneEquation describes the equation as being Ax+By+Cz+D=0, so I think the constructor description is indeed mistaken.

Yes I see that. I’ll see to updating the comments.


– Dale