Compliant mechanisms, particularly helicoidal shell joints, present intriguing possibilities in mechanical design with applications in medical devices, robotics, automotive, and aerospace engineering. This research focuses on the synthesis of nonlinear torque-angle profiles using a compliant helicoidal shell mechanism such as gravity-balancing profiles. This study required a thorough exploration of the mechanism’s diverse design variations through Finite Element Modeling (FEM) and more specifically, Isogeometric Analysis (IGA). Subsequently, a targeted optimization process is utilized, incorporating both global geometric parameter adjustments and localized modifications by using splines. The prominent challenge addressed is the synthesis of gravity balancing torque-angle profile, achieved by tailoring the output profile of a compliant shell mechanism through optimization. Considering the inherent sine function output of a pendulum during gravitational equilibrium, an algorithm is developed to optimize the mechanism’s behavior to align with a sine function, hence enabling gravity balancing. Additionally, experimental validation was undertaken through manufacturing prototypes and conducting measurements to provide a crucial link between simulations and real-world behavior. The results of this research, encompassing optimized geometry and experimental data, are presented, and comprehensively discussed. This research contributes a numerical methodology that utilizes isogeometric analysis and optimization algorithm within the framework of finite element analysis for achieving nonlinear torque-angle profiles in complaint helicoidal shell mechanisms, such as gravity balancing profiles, offering valuable insights for possible applications in various engineering domains.