STKO | Scientific ToolKit for OpenSees |

STKO (Scientific ToolKit for OpenSees) is a powerful pre and post processor and cutting-edge data visualization tool for Opensees. By using STKO a user can create a Tool Command Language (TCL) input file for Opensees and an output file readable by its graphic interface. The user can customize and manipulate with a Python-based scripting interface the model input and output to create customized engineering demand parameters and output data.


We will soon be online with our new platform dedicated to STKO (Scientific Toolkit for OpenSees)
where all interested users can take part in our WEBINARS
on the correct use of STKO software. For more information, write to our email address: [email protected]


Post processing of shell results at gauss points and at through-the-thickness integration points (fibers).

Post processing of beam-column results by means of a fiber-section plot, that allows the user to visualize results such as strain/stress at each fiber of each gauss points of beam-column elements.

Meshing algorithms in STKO pre-processor. Global and local edge seed, unstructured and structured mesh algorithms, triangle/tetrahedron, quadrilateral/hexahedron, linear and quadratic interpolations.

Post processing of beam-column results by means of a gauss-point plot, that allows the user to visualize results such at each gauss points of beam-column elements.

STKO pre-processing for micro-modeling of masonry structures

STKO Seismic Isolation

Simulation of Damage Evolution of Pazzi Chapel in Florence, Italy.
| courtesy of Sabrina Giancola - master degree |


Post-processing of a soil-foundation-structure-interaction problem. Visualization of results on solid elements by means of a volume plot.

Example of absorbing boundaries using the VS3D4 element available in OpenSees.

Comparative study of different approches to simulate absorbing boundaries in soil-structure interaction problems.

3D Analysis of Soil-Pile interaction with contact elements.

Simulation SFSI (Soil Foundation Structure Interaction). Courtesy of Jenny Ramirez Calderon – PhD thesis

SFSI: Analysis of the boundary conditions and their application in the case study of a bridge | Autostrada BS-PD | courtesy of Luca Sallese - master degree |

WHY Scientific ToolKit for Opensees IS SO INNOVATIVE


… features advanced CAD modeling tools, import-export of common CAD file formats, geometry repair tools, and a comprehensive set of meshing algorithms.

… is easily customizable via a python-based scripting interface. So custom components can be easily specified and added to the standard document, to fit the end-user needs.

… can then produce input files for OpenSees with all the information inputed by the user.


Import-export of open file formats (STEP and IGES)

Curve modeling

Surface modeling

Solid modeling

Interface modeling



Linear | Quadratic


Edge Seed:

Uniform by divisions

Uniform by size

Biased by size and bias factor

Biased by number and bias factor

Dual-biased by size and bias factors


2D un-structured for triangles and quadrilaterals

3D un-structured for tetrahedrons

2D structured for triangles and quadrilaterals

3D structured for hexahedrons



Uniaxial | nD



Beam fiber-section

Shell layered-section


SP constraints

MP constraints


Uniform exitation pattern

Multi-support exitation pattern






… features all common visualization algorithms (edge/surface color map, volume rendering, iso-lines, iso-surfaces, vector plots, etc..). Post processing also includes advanced visualization algorithms for beam/column and shell elements equipped with discretized (fiber) cross sections.

… is easily customizable via a python-based scripting interface. Therefore, results can be estracted and manipulated using custom python-scripts, allowing the end-user to produce custom information.

Finally, STKO uses an efficient opensource third-party database library for storing results, the HDF5 database library. The MPCORecorder is a new recorder class for OpenSees that allows OpenSees to write results data in the format required by STKO.

All these features in one Software: STKO, a revolutionary visualization toolkit for Opensees


Save/Load existing post-processor files (restore plots, charts, etc.)

Import of one or multiple MPCO output databases


Deformed shape

Surface color map

Volume color map

Gauss-point plot

Beam/Shell fiber-section plot

Vector plot

Iso-surface plot



Extract data from database:

Extract data from nodes

Extract data from gauss points

Extract data from fibers

Create 2D Charts


Python scripting interface

Add new user-defined components for pre-processing

Extend STKO built-in interfaces for OpenSees components

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