PSET
Give a name to a selected set of points.
seq forms a pset of the nodes in ifirst, ilast, istride;
the special sets: 1,0,0 refers to all nodes and 0,0,0 refers to the last set of nodes created.
union, inter and not are logical operations on previously defined psets.  The definition of the unary operator not is extended such that not/p1/p2 means p1 and (not(p2)).
list lists nodes in a pset or names of all psets
delete deletes a previously defined pset
attribute  forms a pset from all points in ifirst,ilast,istride which have the specified value for a node based attribute. This option was previously named zq.
If the optional comparator field is given; that operation is used to compare the attribute value to the requested value.
geom/xyz/ forms a pset from all points inside the box whose corners are xl,yl,zl and xu,yu,zu relative to the geometry center at xc,yc,zc.
geom/rtz/ forms a pset of nodes within the cylinder or cylindrical shell given by radius r1 to r2, angle t1 to t2 and height z1 to z2.
geom/rtp/ forms a pset of nodes within the sphere, sperical shell or sperical section given by r1 to r2, and angles t1 to t2 and p1 to p2.  See chapter II, A. Conventions for an explanation of angles theta and phi.
surface identifies nodes on the specified surface.  Keyword surface names have the following meaning:
-all- will identify nodes on any surface.
-interface- will identify nodes on any interface surface.
-boundary- will idendify nodes on exterior surfaces.
eltset form a pset of nodes in the element set listed.
constraints forms a pset of nodes having the specified number of constraints.  The node's icr value is used as an index to the icontab attribute which gives the number of constraints.  See chapter III, A for an explanation of the icontab entries. FORMAT: pset/pset name/ seq/ifirst,ilast,istride
union|inter|not|delete/pset1[/pset2/.../psetn]
list
delete
attribute/attribute /ifirst,ilast,istride/value/
  [le| gt| gt| ne| eq]
zq/attribute /ifirst,ilast,istride/value/[le| gt| gt| ne| eq]
region/region name/ifirst,ilast,istride
mregion/mregion name/ifirst,ilast,istride will return all nodes that are in the specified mregion - the definition of the mregion is evaluated to determine membership.  Hence the result may vary from what would be returned if the 'imt1' value of the nodes had been queried using the attribute option geom/xyz/ifirst,ilast,istride/xl,yl,zl/xu,yu,zu/xcen,ycen,zcen
geom/rtz/ifirst,ilast,istride/r1,t1,z1/r2,t2,z2/xcen,ycen,zcen
geom/rtp/ifirst,ilast,istride/r1,t1,p1/r2/t2/p2/xcen,ycen,zcen

surface/surface_name/[ifirst,ilast,istride]

surface will select nodes that are on the specified surface.  If -interface- is specified for the surface name, all interface  nodes  will be returned.  If -boundary- is specified for the surface name, all nodes on external bounding surfaces will be returned. If -all- is specified all nodes on any surface are returned. eltset/element_set_name eltset will return all nodes that are vertices of the elements in the specified element set constraints/number_of_constraints/ifirst,ilast,istride   EXAMPLES: pset/apset/seq/1,0,0/
 associate the pset name apsetwith all points.
pset/apset/seq/0,0,0/
 associate the pset name apsetwith the last set of nodes created.
pset/apset/union/pset1,pset2,pset
 associate the pset name apset with the set of nodes which belong to at least one of pset1, pset2, pset3.
pset/apset/inter/pset1,pset2,pset3
   associate the pset name apset with the set of nodes which belong to pset1, and pset2, and pset3.
pset/apset/not/pset1,pset2,pset3
   associate the pset name apset with the set of nodes which belong to pset1, and do not belong to pset2, and do not belong to pset3
pset/apset/not/pset1
   associate the pset name apset with the set of nodes which do not belong to pset1
pset//list/
   list the names of all psets
pset/apset/attribute/itp/1,0,0/10/ge
   associate the name apset with the points whose type field(itp1) has value greater than or equal to 10 (these would be boundary nodes).
pset/mypset/list
   list the node numbers of the members of mypset
pset/mypset/geom/xyz/1,0,0/1.,1.,-5./10.,20.,10./
   associate the name mypset with all nodes that fall with the box with corners at (1,1,-5) and (10,20,10)
pset/mypset/geom/rtz/pset,get,oldpset/0.,0.,0./10.,360.,10.   associate the name mypset with the nodes that are members of the pset oldpset and which fall inside the cylinder of radius 10 and height 10 and whose axis is the z-axis.
pset/spset/surface/s1/1,0,0
  associate the name spset with the set of nodes that lie on the surface s1.
pset/spseta/surface/s2/pset,get,spset
  associate the name spseta with the set of nodes that lie on the surface s2 and which are members of the pset spset  This command and the previous command would identify the nodes that are on the intersection of surfaces s1 and s2 and give the name spseta to these nodes.
pset/mypset/constraints/3
 associate the name mypset with the set of nodes that have 3 constraints ( normally the set of nodes that lie on 3  constrained surfaces -- surfaces of type reflect or intrcons) Click here for demos