Projecting fields between different meshes commonly arises in computational
physics. This operation requires a supermesh construction and its computational
cost is proportional to the number of cells of the supermesh n. Given any two
quasi-uniform meshes of nA and nB cells respectively, we show under
standard assumptions that n is proportional to nA+nB. This result
substantially improves on the best currently available upper bound on n and
is fundamental for the analysis of algorithms that use supermeshes