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Supported Elements

ops-post recognizes 61 OpenSees element types through its element registry (ops_elements.py).

Shell elements

Displayed as transparent extrusion + mid-surface + fiber layers + GP spheres.

Element Nodes GPs Notes
ASDShellQ4 4 2x2 General-purpose shell
ShellMITC4 4 2x2 Mixed interpolation
ShellDKGQ 4 2x2 Discrete Kirchhoff
ShellNLDKGQ 4 2x2 Nonlinear DKG
ShellANDeS 4 2x2 ANDeS formulation
shellMITC4Thermal 4 2x2 Thermal variant
shellNLDKGQThermal 4 2x2 Thermal variant
ASDShellT3 3 3 Triangular shell
ShellDKGT 3 3 Triangular DKG
ShellNLDKGT 3 3 Triangular nonlinear
ShellMITC9 / ShellNL 9 3x3 9-node shell

2D continuum elements

Displayed the same as shell elements (surface + extrusion).

Element Nodes GPs
quad 4 2x2
quad3d 4 2x2
SSPquad 4 2x2
bbarQuad 4 2x2
enhancedQuad 4 2x2
quadWithSensitivity 4 2x2
nineNodeQuad 9 3x3
Tri31 3 1

Beam / column elements

Displayed as 3D hexahedra using the cross-section profile derived from TCL section data (A, Iz -> rectangular width and height).

Element Nodes
ElasticTimoshenkoBeam2d / 3d 2
elasticBeamColumn 2
forceBeamColumn 2
forceBeamColumnCBDI / CSBDI 2
forceBeamColumnThermal 2
forceBeamColumnWarping 2
elasticForceBeamColumn 2
elasticForceBeamColumnWarping 2
dispBeamColumn 2
dispBeamColumnInt 2
dispBeamColumnThermal 2
dispBeamColumnWithSensitivity 2
gradientInelasticBeamColumn 2
internalBeamColumnElement 2
AxEqDispBeamColumn2d 2
element2dGNL 2
MVLEM / MVLEM_3D 2
SFI_MVLEM / SFI_MVLEM_3D 2
E_SFI_MVLEM_3D 2

Truss elements

Displayed as thin beams with a default square cross-section.

Element Nodes
truss / Truss 2
corotTruss / corotTrussSection 2

Recognized but not visualized (no geometry to display).

Element Type
twoNodeLink / TwoNodeLink Link
zeroLength / ZeroLength Zero-length
zeroLengthSection Zero-length
zeroLengthND Zero-length
zeroLengthContact2D / 3D Zero-length
zeroLengthContactASDimplex Zero-length
zeroLengthImpact3D Zero-length
zeroLengthInterface2D Zero-length
zeroLengthRocking Zero-length
CoupledZeroLength Zero-length

Unknown elements

If an element type is not in the registry, ops-post falls back to guessing the topology from the connectivity column count:

Columns Assumed type
4 Shell quad (Q4)
3 Shell triangle (T3)
9 9-node quad (Q9)
2 Beam

To add a missing element, see Extending.