- Vector4 x_axis = *matrix*Vector4(1.0f, 0.0f, 0.0f, 0.0f);
- float radius_sq = bsphere->get_radius()*inner_product(x_axis, x_axis);
+ Vector3 x_axis = (matrix->column(0)*bsphere->get_radius()).slice<3>(0);
+ float radius_sq = inner_product(x_axis, x_axis);