We calculate bubble-nucleation rates for (2+1)-dimensional scalar theories at
high temperature. Our approach is based on the notion of a real coarse-grained
potential. The region of applicability of our method is determined through
internal consistency criteria. We compare our results with data from lattice
simulations. Good agreement is observed when the renormalized action of the
simulated theory is known.Comment: 12 pages, 2 figures. Final version; minor misprints correcte