I have some data that I am trying to figure out what the meaning of it is, relating to 3d Geometry (using cartesian axes of Y = up).
The data is a binary tree, with each node having a left and a right node child, each node having an equation of the form Ax + Bz + C. Each final leaf node, has a lookup to a plane equation, if Ax + Bz + C < 0, or another, if >= 0, and then it uses that plane to return a Y coordinate based on the input X and Z.
The tree is traversing by inputting the X and Z coordinate in the tree, starting at the topmost node (into x and z), finding if the node's Ax + Bz + C < 0 (go left node), or >= 0 (go right node), and repeating until hitting a leaf. Finally, when it hits a leaf, if Ax + Bz + C < 0, it inputs the XZ data into the left Plane looked up, and gets a Y coordinate back, or if it is >= 0, it inputs the X and Z into the right Node's plane equation and gets a Y back.
The whole process seems to be a traversing a tree to find the best choice of plane for a given X and Z input (but I can't figure out what the main binary tree is doing, how are these Ax + Bz + C < 0 equations localizing?), then using that plane to lookup Y coordinates, based on inputting X and Z, but I cannot figure out the meaning of the Ax + Bz + C < 0 binary tree. The plane lookup at the end is of standard form (Ax + By + Cz + D = 0).
$Ax+Bz+C=0$ is the equation of a plane parallel to $y$-axis. If $Ax+Bz+C>0$, then point $(x,y,z)$ is on the "positive side" of the plane, that is on the side pointed to by vector $(A,0,B)$ (which is perpendicular to the plane). If, on the other hand, $Ax+Bz+C<0$, then point $(x,y,z)$ is on the "negative side" of the plane.
I don't know the details in your case, but a simple example could be when all planes are parallel: the binary tree could then be a way to decide between which adjacent planes the point is located.