A method for visualizing ablation includes displaying to a user a three-dimensional (3D) tube that visually represents a region for ablation in tissue of a patient. Ablation information, which specifies one or more ablation locations along the 3D tube and one or more respective ablation configurations for ablating in the ablation locations, is received from the user. An estimated impact of the ablation in the tissue is displayed to the user on the 3D tube based on the ablation locations and the corresponding ablation configurations.