Geometry and quasisymmetric parametrization of Semmes spaces

We consider decomposition spaces $\R^3/G$ that are manifold factors and admit defining sequences consisting of cubes-with-handles. Metrics on $\R^3/G$ constructed via modular embeddings into Euclidean spaces promote the controlled topology to a controlled geometry. The quasisymmetric parametrizability of the metric space $\R^3/G\times \R^m$ imposes quantitative topological constraints, in terms of the circulation and growth, to the defining sequences for $\R^3/G$. We give a necessary condition and a sufficient condition for the existence of parametrization. The necessary condition answers a question of Heinonen and Semmes on quasisymmetric parametrizability of spaces associated to the Bing double. The sufficient condition gives new examples of quasispheres in $\bS^4$.