Consider a simply connected domain Ω ⊂ R2 with boundary ∂Ω that is given by a smooth function φ : [a, b] 7→ R2. Our goal is to calculate a diffeomorphism Φ: B1(0) 7→ Ω, B1(0) the open unit disk in R2. We present two different methods where both methods are able to handle boundaries ∂Ω that are not star-shaped. The first method is based on an optimization algorithm that optimizes the curvature of the boundary, and the second method is based on the physical principle of minimizing a potential energy. Both methods construct first a homotopy between the boundary ∂B1(0) and ∂Ω and then extend the boundary homotopy to the inside of the domains. Numerical examples show that the method is applicable to a wide variety of domains Ω. Copyright © 2022, Kent State University.