Controlling Dendritic Ice and Frost Crystal Growth Along User‐Drawn Trajectories

ABSTRACT This paper proposes a method to control the growth of dendritic crystals, such as ice and frost, along trajectories specified by the user. The growth of dendritic crystals involves numerous parameters, requiring extensive trial and error to achieve the shapes intended by artists. To address this problem, we generate target shapes and external forces that follow the user‐specified shape and use these to control the behavior of the temperature field and particles representing the water molecules. The external forces consist of a guiding force that generates a reverse flow along the user‐drawn trajectory to facilitate particle arrival at the reaction front and a driving force that attracts particles toward the target shape. Furthermore, to prevent the crystal from growing beyond the target shape, a field representing the freezing temperature of ice and frost is set according to the target shape. The experimental results demonstrated that it is possible to generate ice and frost animations that grow along user‐specified shapes, such as character‐like forms.