Heinz Isler strongly believes that the work of the architect and the engineer cannot be separated in shell design because of its inherent integration of aesthetics and statics.

[An] ideal architect-engineer relationship is epitomized by the collaboration of Heinz Isler and Michael Balz... Isler taught Balz various form-finding methods, and consequently the architect began to design his own creative shells by exploring hanging membranes and inflated forms.

Although Isler and Balz only worked on a few projects together in Germany, the resulting shells (including the Naturtheater Grötzingen, the Stetten Theater, and the Balz House) are some of the most elegant works that Isler produced in his career.