Dist2Walls: wall distance computation
Preamble
Dist2Walls gathers efficient algorithms for computing the distance fields for arrays (as defined in Converter documentation) or for CGNS/python tree (pyTrees).
This module is part of Cassiopee, a free opensource pre and postprocessor for CFD simulations.
For use with the array interface, you have to import Dist2Walls module:
import Dist2Walls
For use with the pyTree interface:
import Dist2Walls.PyTree
List of functions
– Wall distance computation

Compute distance to walls. 
Contents
Wall distance computation

Dist2Walls.
distance2Walls
(a, bodies, type='ortho', loc='centers', signed=0, dim=3) Computes the distance field from a set of bodies. compute the distance field located at nodes or centers of zone a (or zones in A), provided a list of surfaces defining the bodies to which the distance is computed.
Two algorithms are available:
type=’ortho’ means a distance computed by an orthogonal projection to the surface faces defined by bodies.
type=’mininterf’ returns the minimum distance of the point to the vertices of bodies.
If loc=’nodes’, returns a distance computed at nodes of a (A), else if loc=’centers, distance is computed at cell centers of a (A).
Parameter ‘signed’=1 enables to compute a signed distance (negative inside bodies). When using signed distances, each body in bodies list must be a closed and watertight surface. In array version, cellnbodies provides the ‘cellN’ field for any vertex in bodies. Default value is 1. The algorithm ‘ortho’ does not take into account a body face if cellN=0 for all the vertices of that face. The algorithm ‘mininterf’ does not compute the distance to a vertex of cellN=0.
 Parameters
a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – input data
bodies ([array, list of arrays] or [pyTree, base, zone, list of zones]) – body definition
type (string) – type of wall distance computation in [‘ortho’, ‘mininterf’]
loc (string) – location of distance field in [‘nodes’, ‘centers’]
signed (int) – if 0 absolut distance, if 1 signed distance (negative inside)
In the pyTree version, ‘cellN’ variable must be stored in bodies directly. If loc=’nodes’, the distance field is stored as a ‘TurbulentDistance’ field located at nodes, and if loc=’centers’, it is stored in nodes located at centers.
Exists also as an inplace version (_distance2Walls) that modifies a and returns None.
Example of use:
#  distance2Walls (array)  import Dist2Walls import Generator as G import Converter as C import Geom as D # Bloc dont on cherche la distance a la paroi a = G.cart((0.,0.,0.),(0.1,0.1,0.1),(10,10,10)) # Paroi sphere = D.sphere((1.2,0.,0.), 0.2, 30) cellN = C.initVars(sphere,'cellN',1.) # Calcul de la distance a la paroi dist = Dist2Walls.distance2Walls(a, [sphere], cellnbodies=[cellN], loc='centers',type='ortho') ac = C.node2Center(a) ac = C.addVars([ac, dist]) C.convertArrays2File([ac], 'out.plt')
#  distance2Walls (pyTree)  import Dist2Walls.PyTree as Dist2Walls import Generator.PyTree as G import Converter.PyTree as C import Geom.PyTree as D a = G.cart((0.,0.,0.),(0.1,0.1,0.1),(10,10,10)) sphere = D.sphere((1.2,0.,0.),0.2,100) t = C.newPyTree(['Base',a]) t = Dist2Walls.distance2Walls(t, sphere) C.convertPyTree2File(t, 'out.cgns')