This paper presents theory for the Lagrange co-rotational (CR) formulation of
finite elements in the geometrically nonlinear analysis of 3D structures. In
this paper strains are assumed to be small while the magnitude of rotations
from the reference configuration is not restricted. A new best fit rotator and
consistent spin filter are derived. Lagrange CR formulation is applied with
Hybrid Trefftz Stress elements, although presented methodology can be applied
to arbitrary problem formulation and discretization technique, f.e.