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doc:user:geometry:user:selections

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doc:user:geometry:user:selections [2013/07/12 13:31] – external edit 127.0.0.1doc:user:geometry:user:selections [2018/01/30 18:46] (current) papeleux
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 +====== Node Groups ======
  
 +Node selections are used to apply boundary conditions ([[doc:user:conditions:displacements]]) or to extract curves ([[doc:user:results:courbes_res]]) on a specific node set which does not initially come from a geometric entity. In Metafor, a selection is represented by a ''Group''. This object is a virtual geometric entity which can possess nodes, in the same way as other entities receive them when they are meshed.
 +
 +===== ''Group'' Creation =====
 +
 +A ''Group'' is defined as any other geometric entity.
 +
 +  groupset.add( Group(number) )
 +
 +===== Information on the nodes of a ''Group'' =====
 +
 +Some functions can be used to obtain data on some nodes of a ''Group'': 
 +
 +  grp = groupset(number)
 +  
 +  grp.getNo()                 # Returns the number of the group grp 
 +  grp.getNumberOfMeshPoints() # Returns the number of meshedPoints in the ''Group'' grp 
 +  grp.getMeshPoint(idx)       # Returns a reference towards the idxth MeshedPoint of the group grp.
 +
 +===== Adding nodes (simple) =====
 +
 +  groupset(number).add(GObject)
 +  groupset(number).addMeshPoint(no)
 +  groupset(number).addMeshPointsInBox(xmin, xmax, ymin, ymax, zmin, zmax)
 +  groupset(number).addMeshPointsFromObject(target, selector)
 +  groupset(number).addInnerMeshPointsFromObject(target, selector) 
 +  
 +where
 +
 +| ''number'' | group number | 
 +| ''no''     | number of the node ((it is more of a ''MeshPoint'', so a mesh point which can be found in ''domain.getTopology().getPointSet()'')) to add to the group| 
 +| ''xmin'', ''ymin'', ''zmin'' | lower corner of the selection box| 
 +| ''xmax'', ''ymax'', ''zmax'' | upper corner of the selection box| 
 +| ''target''   | geometric entity used as support | 
 +| ''selector'' | selection operator which reduces the number of MeshPoints in the group | 
 +
 +nb : addInnerMeshPointsFromObject does not add nodes on boundary of ''target'' if ''target'' is a real geometrical object (meaning : not a group)
 +
 +===== Sorting the selected nodes =====
 +
 +It is not always easy to select only the required nodes (on parametric studies for example). Therefore, it is possible to sort a selection, in order to select a subset of this first selection. This is done done with [[doc:user:general:sortingoperator]].
 +
 +  groupset(number).selectMeshPoints(sorter,nbMeshPoints)
 +
 +where
 +| ''number'' | group number| 
 +| ''sorter'' | sorting operator| 
 +| ''nbMeshPoints'' | number of ''MeshPoints'' which will remain in the group | 
 +
 +__Example:__
 +
 +  group.addMeshPointsFromObject(sideset(1))
 +  group.selectMeshPoints(SortByNo(),3) 
 +
 +These lines sort the nodes by user number and conservation of three values.
 +
 +===== Advanced features (Selectors) =====
 +
 +Adding nodes from the geometric object ''target'' (target can be a group):
 +
 +  groupset(number).addMeshPointsFromObject(target, selector)
 +
 +where ''selector'' is an object of the ''Selector'' type. Here are some of its derived classes:
 +
 +=== BoxSelector===
 +
 +Selection within a box : 
 +
 +  BoxSelector(xMin, xMax, yMin, yMax, zMin, zMax)
 +
 +where
 +| ''xMin'' | minimal X value | 
 +| ''xMax'' | maximal X value | 
 +| ''yMin'' | minimal Y value | 
 +| ''yMax'' | maximal Y value | 
 +| ''zMin'' | minimal Z value | 
 +| ''zMax'' | maximal Z value | 
 +
 +=== RangeSelector ===
 +
 +Selection in a given area : 
 +
 +  RangeSelector(lock, vMin, vMax)
 +
 +where
 +| ''lock'' | direction of the selector : ''TX'', ''TY'' or ''TZ''
 +| ''vMin'' | minimal value in lock direction | 
 +| ''vMax'' | maximal value in lock direction | 
 +
 +=== DistSelector ===
 +
 +Spherical selection : 
 +
 +  DistSelector (Cx, Cy, Cz, R)
 +
 +where
 +| ''Cx, Cy, Cz'' | center of the sphere | 
 +| ''R'' | radius of the sphere | 
 +
 +=== SectorSphericalSelector ===
 +
 +Selection in a spherical sector : 
 +
 +  SectorSphericalSelector (Cx, Cy, Cz, rMin, rMax, thetaMin, thetaMax, phiMin, phiMax)
 +
 +where
 +| ''Cx, Cy, Cz'' | center of the spherical sector | 
 +| ''rMin''- ''rMax'' | minimal - maximal radius of the spherical sector | 
 +| ''thetaMin''-''thetaMax'' | minimal-maximal azimuth angle (from $0.0$ to $2 \pi$) | 
 +| ''phiMin''-''phiMax'' | minimal-maximal elevation angle (from $-\frac{\pi}{2}$ to $\frac{\pi}{2}$) | 
 +
 +__Note__ : angles are computed with respect to the structural frame translated toward the center or the sphere. 
 +
 +=== AnnealedSelector ===
 +
 +Selection selection of a ring along the ''x'', ''y'' or ''z'' direction : 
 +
 +  AnnealedSelector(lock, x, y, z, rMin, rMax, hMin, hMax)
 +
 +where
 +| ''lock''  | direction of the axe of the ring (''TX'', ''TY'' or ''TZ'') | 
 +| ''x,y,z'' | center of the ring | 
 +| ''rMin,rMax'' | minimal - maximal radius of the ring | 
 +| ''hMin,hMax'' | minimal - maximal height of the ring | 
 +
 +gets all nodes situated from the two cylinders of axis ''lock'', of radii ''rMin'' and ''rMax'', and of height between ''hMin'' and ''hMax''.
 +
 +=== SectorAnnealedSelector ===
 +
 +Selection of a part or a ring, defined by two angles, along the ''x'', ''y'' or ''z'' direction : 
 +
 +  SectorAnnealedSelector(lock, x, y, z, rMin, rMax, thetaMin, thetaMax, hMin, hMax)
 +
 +where
 +| ''lock''  | direction of the axe of the ring (''TX'', ''TY'' or ''TZ'') | 
 +| ''x,y,z'' | center of the ring | 
 +| ''rMin, rMax'' | minimal - maximal radius of the ring sector | 
 +| ''thetaMin, thetaMax'' | minimal - maximal angle of the sector (from $-\pi$ to $\pi$) | 
 +| ''hMin, hMax'' | minimal - maximal height of the ring sector | 
 +
 +=== TorrusSelector ===
 +
 +Selection of nodes inside a torus :
 +
 +  TorrusSelector(axe, Cx, Cy, Cz, rMin, rMax)
 +
 +where
 +| ''axe'' | [[doc:user:geometry:user:axes|Axe]] of the torus  | 
 +| ''Cx, Cy, Cz'' | center of the torrus | 
 +| ''rMin'' | minimal Radius (to be explained) | 
 +| ''rMax'' | maximal Radius (to be explained) | 
 +
 +=== EllipseSelector ===
 +
 +Selection within an ellipse :
 +
 +  EllipseSelector (lock, Cx, Cy, CZ, a, b)
 +
 +where
 +| ''lock'' | direction of axe perpendicular to the plane of the ellipse : ''TX'', ''TY'' or ''TZ''
 +| ''Cx, Cy, Cz'' | center of the ellipse |
 +| ''a'' | small radius | 
 +| ''b'' | big radius | 
 +
 +
 +=== PlaneSelector ===
 +
 +Selection on one side of a plane :
 +
 +  PlaneSelector (plane, dir)
 +
 +where
 +| ''plane'' | [[doc:user:geometry:user:surfaces#plane|Plane]] surface object | 
 +| ''dir'' | boolean (True / False) defining the side of the plane (depending to the normal) |
 +
 +=== BoundarySelector ===
 +
 +Select nodes that are on the surface of a meshed object (3D Models only)  :
 +  BoundarySelector ()
 +
 +=== Boundary2DSelector ===
 +
 +Select nodes that are on the surface of a meshed object (2D Models only)  :
 +
 +  Boundary2DSelector ()
 +
 +=== InverseSelector ===
 +
 +Revert the effect of a selector  :
 +
 +  InverseSelector (selector)
 +
 +where
 +| ''selector'' | selector whose effect will be inverted | 
 +
 +__Examples:__
 +
 +  group.addMeshPointsFromObject(sideset(1), RangeSelector(TX, xmin, xmax))  
 +
 +gets all nodes from side #1 whose ''x'' coordinate is between ''xmin'' et ''xmax''.
 +
 +  group.addMeshPointsFromObject(sideset(1), BoxSelector(xmin, xmax, ymin, ymax, zmin, zmax))
 +
 +gets all nodes from side #1 in the rectangular box defined by ''xmin'', ''xmax'', ''ymin'', ''ymax'', ''zmin'', ''zmax''.
 +
 +   group.addMeshPoints(DistSelector(x, y, z, R))
 +
 +gets all nodes situated in a sphere of center ''(x,y,z)'' and radius ''R''.
 +
 +   group.addMeshPoints(SectorSphericalSelector(Cx, Cy, Cz, rMin, rMax, thetaMin, thetaMax, phiMin, phiMax)) 
 +
 +gets all nodes in the spherical sector of center (Cx,Cy,Cz), of minimal and maximal radii rMin and rMax, of minimal and maximal azimuth angle thetaMin and thetaMax, and of minimal and maximal elevation angle pHiMin and phiMax.
 +
 +__Note__ : angles are computed with respect to the structural frame translated toward the center or the sphere. The elevation angle varies from $-\frac{\pi}{2}$ to $\frac{\pi}{2}$ and the azimuth angle from $0.0$ to $2 \pi$.
 +
 +  group.addMeshPoints(TorrusSelector(Axe(curveset(1)), Cx, Cy, Cz, rMin, rMax))
 +  
 +gets all nodes in the toroidal sector defined by the revolution axis Axe(curveset(1)), the annular cross section centroid is (Cx, Cy, Cz) (This is the cross section used in the revolution mesher.) and the minimal and maximal radii rMin and rMax.
 + 
 +  group.addMeshPoints(AnnealedSelector(TX, x, y, z, rMin, rMax, zMin, zMax))
 +
 +gets all nodes situated from the two cylinders of axis ''TX'', of radii ''rMin'' and ''rMax'', and of height between ''zMin'' and ''zMax''.
 +
 +  group.addMeshPoints(SectorAnnealedSelector(TX, x, y, z, rMin, rMax, thetaMin, thetaMax, zMin, zMax))
 +
 +gets all nodes situated within two parts of cylinders of axis ''TX'', of opening angle between ''thetaMin'' and ''thetaMax'', of radii ''rMin'' and ''rMax'', and of height between ''zMin'' and ''zMax''.
 +
 +{{ doc:user:selectors.gif |Selectors}}

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