12. elements — Element local coordinates and numbering.

Element local coordinates and numbering.

This modules allows for a consistent local numbering scheme throughout pyFormex. When interfacing with other programs, one should be aware that conversions may be necessary. Conversions to/from external programs should be done by the interface modules.

class elements.Element

Element base class: an empty element.

All derived classes should have a capitalized name: starting with an uppercase character and further only lower case and digits.

Each element is defined by the following attributes:

  • vertices: the natural coordinates of its vertices,
  • edges: a list of edges, each defined by a couple of node numbers,
  • faces: a list of faces, each defined by a list of minimum 3 node numbers,
  • element: a list of all node numbers
  • drawfaces: a list of faces to be drawn, if different from faces. This is an optional attribute. If defined, it will be used instead of the faces attribute to draw the element. This can e.g. be used to draw approximate representations for higher order elements for which there is no correct drawing function.

The vertices of the elements are defined in a unit space [0,1] in each axis direction.

The elements guarantee a fixed local numbering scheme of the vertices. One should however not rely on a specific numbering scheme of edges, faces or elements. For solid elements, it is guaranteed that the vertices of all faces are numbered in a consecutive order spinning positively around the outward normal on the face.

Methods

Element objects have the following methods:

nvertices()
nedges()
nfaces()
getFaces()
class elements.Point

A single node element

Methods

Point objects have the following methods:

class elements.Line2

A 2-node line segment

Methods

Line2 objects have the following methods:

class elements.Tri3

A 3-node triangle

Methods

Tri3 objects have the following methods:

class elements.Tri6

A 6-node triangle

Methods

Tri6 objects have the following methods:

class elements.Quad4

A 4-node quadrilateral

Methods

Quad4 objects have the following methods:

class elements.Quad8

A 8-node quadrilateral

Methods

Quad8 objects have the following methods:

class elements.Quad9

A 9-node quadrilateral

Methods

Quad9 objects have the following methods:

class elements.Tet4

A 4-node tetrahedron

Methods

Tet4 objects have the following methods:

class elements.Wedge6

A 6-node wedge element

Methods

Wedge6 objects have the following methods:

class elements.Hex8

An 8-node hexahedron

Methods

Hex8 objects have the following methods:

class elements.Icosa

An icosahedron: a regular polyhedron with 20 triangular surfaces.

nfaces = 20, nedges = 30, nvertices = 12

Methods

Icosa objects have the following methods:

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