Experimental and theoretical studies of excitation of the 3³D state of helium by 40 eV electrons are reported. Experimentally, electron-photon polarization correlations are measured in the scattering plane defined by the incident and scattered electron momenta. These are combined with previously reported linear and circular polarization measurements perpendicular to the scattering plane. After allowing for the effects of fine structure depolarization, parameters describing the shape and dynamics of the excited state produced in the collision are determined. Theoretically, the measured polarizations and excited state parameters are predicted using the convergent close coupling (CCC) theory. Excellent agreement is obtained between the experimental and theoretical results.