public RTMesh(Mesh unityMesh)
{
_unityMesh = unityMesh;
_vertices = _unityMesh.vertices;
_vertIndices = _unityMesh.triangles;
_numTriangles = (int)(_vertIndices.Length / 3);
_meshTree = new MeshTree(this);
_aabb = new AABB(_unityMesh.bounds);
}