That's also how Eigen defines it: https://libeigen.gitlab.io/eigen/docs-nightly/classEigen_1_1Hyperplane.html https://libeigen.gitlab.io/eigen/docs-nightly/clas

That's also how Eigen defines it: https://libeigen.gitlab.io/eigen/docs-nightly/classEigen_1_1Hyperplane.html https://libeigen.gitlab.io/eigen/docs-nightly/classEigen_1_1... Basically this is the ax^2 + bx + c + d = 0 in 3D space.