Given the vertices for a poygon (tri or quad) , the face vertex list, and the normal for the polygon, a single floating point number is also given.

Question is what does the value relate to?

example 1

v1 30.9, 234.51, -4.32
v2 -114.77, 117.93, 36.38
v3 52.97, 117.93, 145.31

normal -0.390294 0.697474, 0.601

unknown value -148.91

example 2

v1 -59.72, 163.79, 98.19
v2 -5.21, 177.91, 16.89
v3 10.44, 119.18, 88.13

normal 0.520179, 0.711538, 0.472364

unknown value -131.862

We are porting a viewer to linux and mac, the unknown value isn't essential for the program, just wondering what it is.

Wow thanks,

never seen that before, any ideas for it's use?

(The program being ported is used to create unfolded nets from 3D geometry.)

FYI, I think the normals are negated not the distance.

The triangle is contained in a plane. If you want to test whether a point is to one side of the plane or the other, you simply check the sign of `dot_product(point - origin, normal) + value'.