Accurate modelling of the right ventricle of the human heart is important for both diagnosis and treatment planning. The right ventricle (RV) has a compound convex-concave shape with several sharp edges. While the RV has previously been modeled using the Doo-Sabin method, these models require several extra control nodes to accurately reproduce the relatively sharp edges. The current paper proposes a modified Doo-Sabin method which introduces weighting of vertices and edges rather than extra nodes to control sharpness. This work compares standard vs sharp Doo-Sabin models on modeling the RV from 16 3D ultrasound scans, compared to a ground truth mesh model manually drawn by a cardiologist. The modified, sharp Doo-Sabin method came closer to the ground truth RV model in 11 out of 16 cases and on average showed an 11.54 % improvement.