Elements: vertices, edges, facets, bodies, facet-edges.

Attributes:

id original coordinates parameter values fixed constraints boundary bare edges facets

valence quantities dihedral square mean curvature triple point tetra point vertexnormal __force __velocity extra attributes

Attributes:

id oid original length density or tension fixed constraints boundary wrap color

bare no_refine orientation vertices midv facets valence backbody frontbody dihedral tangent vector quantities extra attributes

In the string model, a facet is a chain of an arbitrary number of edges. The chain need not be closed. Usually a facet is defined in the string model in order to define a body, so the space dimension is 2 and the facet is planar, one facet corresponding to a body. Facets carry no energy by themselves.

In the simplex model, a facet is a simplex of dimension surface_dimension defined by surface_dimension+1 vertices. The surface_dimension may be any dimension less than or equal to the space_dimension. The simplex is oriented according to the order of the vertices. By default, a simplex carries a surface tension energy proportional to its volume.

Facets may carry additional energy by having named quantity energies applied to them.

The facets of the original surface are defined in the faces section of the datafile.

Attributes:

id oid original area fixed constraints density or tension color frontcolor backcolor no_refine

edges vertices bodies frontbody backbody valence normal vector phase quantities nodisplay extra attributes

Attributes:

facets id density volume target volfixed

actual_volumet volconst pressure phase extra attributes

Element attributes

   list vertex where id < 10
   set edge color red where id == 4 or id == 6 or id == 9
   foreach facet ff do { printf "%g  %g %g %g\n",ff.id,ff.edge[1].id,
      ff.edge[2].id,ff.edge[3].id } 

   foreach facet ff do { printf "%g  %g %g %g\n",ff.id,ff.edge[1].oid,
      ff.edge[2].oid,ff.edge[3].oid } 

   set facet color red where original == 1

   foreach facet do printf "%g %f\n",id,xmoment
   list facet where xmoment > 4
   set facet quantity xmoment where original == 1
   unset facet quantity xmoment

dihedral

  define vertex attribute oldx real
  vertices
  1   2 0 0 oldx 3

  set vertex oldx x
  define edge attribute vibel real[2]
  set edge[2] vibel[1] 3; set edge[2] vibel[2] 4
  print vertex[3].oldx

 define facet attribute minz real function
	 {self.minz := min(self.vertex,z);}

  foreach vertex do printf "%g  %f %f %f\n",id,x,y,z
  set vertex z z+.1*x

  foreach vertex do printf "%g %f\n",id,p1
  set vertex[1] p1 1.2

  list vertex where fixed
  fix vertex where on_constraint 1
  unfix vertices where on_boundary 1

  list vertex where on_constraint 2
  set vertex constraint 1 where id == 4 or id == 6
  unset vertex constraint 3

   list edge where on_constraint 3
   print vertex[3].on_constraint 1

   list vertex where hit_constraint 3
   print vertex[3].hit_constraint 1

  list vertex where on_boundary 1
  unset vertex boundary 2

   list vertex where bare

  list vertex[3].edges
  foreach vertex vv do { foreach vv.edge do print id }

  list vertex[3].facets
  foreach vertex vv do { foreach vv.facet do print id }

  list vertices where valence == 6
  histogram(vertex,valence)

 print vertex[3].vertexnormal[1];
 print vertex[3].vertexnormal[2];
 print vertex[3].vertexnormal[3];
 

 histogram(edge where on_constraint 1, length)
 print edge[3].length

  set edge tension .5 where id < 10
  loghistogram(edge,density)

  fix edge where on_constraint 1
  list edges where fixed
  set edge color red where fixed
  unfix edge[3]

  list edge where on_constraint 2
  set edge constraint 1 where id == 4 or id == 6
  unset edge constraint 3

  list edges where on_boundary 1
  unset edges boundary 2

  list edge where wrap != 0

  set edge color red where length > 1
  show edge where color != black

  list edge where bare

  set edge no_refine where fixed
  unset edge[2] no_refine
  list edge where no_refine
  print edge[3].no_refine

  set edge[2] orientation -1

   list edge[2].vertices
   list edge ee where ee.vertex[1].on_constraint 1 

   list edge[2].facets
   foreach edge ee do print max(ee.facets,area)

  list edges where valence == 1
  refine edge where valence != 2

   list edges where z^2 > 10*(x^2 + y^2)

  list facet where area < .1

  set facet tension 3 where original == 1
  list facet where density < .4

Facet read-write attribute. Putting a facet on a constraint means that every vertex, edge, or facet generated by refining the facet will inherit that constraint. Setting a facet on a constraint does not set any of its existing edges or vertices on the constraint. Facets may be put on constraints in the datafile by listing the constraint numbers after the keyword constraint on the line defining the facet, or with the set command. They may be removed with the unset command. Examples:

  list facets where on_constraint 1
  set facet[2] constraint 2
  unset facet constraint 1

  Faces
  1   1 2 3 color red

  list facets where color == red
  set facet[3] color green
  set facet color red where area > 2

  Faces
  1   1 2 3 frontcolor green backcolor red

  list facets where frontcolor == red
  set facet[3] frontcolor green
  set facet frontcolor red where area > 2

  Faces
  1   1 2 3 frontcolor green backcolor red

  list facets where backcolor == red
  set facet[3] backcolor green
  set facet backcolor red where area > 2

  list facet[3].vertex

  list facet[3].edges

list facet[3].bodies

  newb := new_body; set facet frontbody newb where color == red
  print facet[2].frontbody

  newb := new_body; set facet[1] frontbody newb;
  set facet backbody newb where id == 2 or id == 4;
  print facet[4].backbody

  list facets where valence != 3

   set facet nodisplay where color != red

   set facet[123] orientation -1

   list facet where phase == 1

  list body[1].facets

  print body[2].density
  set body density 3
  body[2].density := 5

• An integral over the facets bounding the body. This is \int z dx dy normally, but \int (x dy dz + y dz dx + z dx dy)/3 if SYMMETRIC_CONTENT is in effect.
• Any constraint content edge integrals applying to the body.
• The body's volconst attribute.

• An integral over the edges bounding the body's facet. This is \int -y dx.
• Any constraint content vertex integrals applying to the body.
• The body's volconst attribute.

  print body[1].volume
  foreach body where volume > 2 do print id

   set body[1] target 23
  unset body target where id == 2
  print body[2].target

  print body[1].volconst
  set body[2] volconst 1.2
  body[2].volconst := 1.2

  print body[2].pressure
  body[2].pressure := 1.3
  set body[2] pressure 1.3