Fig. 1
From: LimeSeg: a coarse-grained lipid membrane simulation for 3D image segmentation
Surfel interaction rules. a - Forces and torque acting on a neighboring pair of surfel. Top left: notation convention for the position and normal vector of surfels. Top right: preferred distance interaction d0 and associated force Fdist. Bottom left, planar interaction Fplane. Bottom right, Ttilt. b - Interaction with the 3D image. Fsignal has a constant norm. It is positive, null, or negative depending on the local image maximum. c - Fpressure exerted along the normal vector. The sign of fpressure controls surface shrinkage or expansion. d - Adaptation of surfel number depending on local neighbors. The number of neighbors within the sphere of influence is counted. Depending on this number, the surfel is removed or a new one is generated