# 8.1.5. particle mesh¶

mesh('part', tag, type, *pArgs, eleType='', *eleArgs=[], '-vel', *vel0, '-pressure', p0)

Create or return a group of particles which will be used for background mesh.

 `tag` (int) mesh tag. `type` (str) type of the mesh `pArgs` (list (float)) coordinates of points defining the mesh region `nx`, `ny`, `nz` are number of particles in x, y, and z directions `'quad'` : [x1, y1, x2, y2, x3, y3, x4, y4, nx, ny] Coordinates of four corners in counter-clock wise order. `'cube'`[x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4,z4, x5, y5, z5, x6, y6, z6, x7, y7, z7, x8, y8, z8, nx, ny, nz] Coordinates of four corners at bottom and at top in counter-clock wise order `'tri'` : [x1, y1, x2, y2, x3, y3, nx, ny] Coordinates of three corners in counter-clock wise order `'line'` : [x1, y1, x2, y2, nx] Coordinates of two ends in counter-clock wise order `'pointlist'`[x1, y1, , vx1, vy1, ,ax1, ay1, , p1, x2, y2, , vx2, vy2, , ax2, ay2, , p2, ..] input particles’ data in a list, in the order of coordinates of last time step, current coordinates, velocity, acceleration, and pressure. `'pointlist'` without list return a list of current particles’ data in this mesh [tag1, x1, y1, , vx1, vy1, , ax1, ay1, , p1, tag2, x2, y2, , vx2, vy2, , ax2, ay2, , p2, ..] The format is similar to the input list, but with an additional tag for each particle. `eleType` (str) the element type, (optional) PFEMElementBubble PFEMElementCompressible Tri31 Element if no type is given, only nodes are created `eleArgs` (list) a list of element arguments. (optional, see line mesh and triangular mesh) `vel0` (list (float)) a list of initial velocities. (optional) `p0` (float) initial pressure. (optional)