Claytex develops a number of Modelica application libraries and related tools for use with Dymola and CATIA Systems. These products are available directly from Claytex and our distributors. We currently develop and maintain the following products:

  • Engines Library

    I4 Mean Value Engine Model  I4 Crank Angle Engine Model
    I4 Crank Angle Engine Model with VCT
    Animation of V8 Engine Model
    V6 Mean Value Engine Model with Turbo
    Common templates for mean value and crank angle modelsEasy to customise to investigate new technologies like VCT and Atkinson cycle enginesAdd turbochargers, superchargers and related components such as intercoolers


    The Engine library is capable of modelling both Spark Ignition and Compression Ignition engines and is split into two variants with different levels of fidelity. Both versions of the Engines library have been designed to work with common engine architecture templates. This enables quick model set-up and ensures a consistent layout for a variety of engine architectures.

    The Mean Value version of the Engines library predicts the cycle averaged intake and exhaust flows, emissions and torque. The Crank Angle Resolved version predicts the complete cyclic intake and exhaust flows and torque.

    Key Features
    Mean Value Version
    Crank Angle Resolved Version
      • Control system development using detailed physical models of internal combustion engines.
      • Supports spark ignition and compression ignition engines as mean-value or crank-angle resolved models.
      • Includes turbocharger and supercharger models for forced induction engines.
      • Captures the full transient response of the engine (air-flow, mechanics and thermal effects).
      • In-vehicle NVH and performance analysis when coupled to the Powertrain and Vehicle Dynamics libraries.
      • Reduction of dyno test time.
      • Repeatable virtual test conditions.
      • Real-time capability.
      • Animation is built-in to the models
      Animation of I4 engine model
    • The Mean Value version predicts the cycle averaged air flow and torque produced by the engine.

      The cylinder mass flow rates are calculated through an equation based approach allowing the engine capacity to be scaled within reasonable limits. This enables downsizing studies to be carried out using the library.

      The combustion and emissions modelling is map based using manifold pressure and engine speed as the primary inputs to the maps with further corrections for spark timing and afr.

      This version of the Engine library is particularly suited to driveability analysis where the effect of throttle transients on the driveline behaviour are investigated. In addition, this version of the library is also suited to catalyst light-off investigations.

      Whole vehicle with detailed engine, powertrain and chassis models
    • The Crank Angle Resolved version predicts the cyclic variations for air flow and torque. This is an extension to the Mean Value version of the library.

      The combustion heat release is modelled though a Wiebe model with table based coefficients. The table defines the Wiebe model coefficients at different engine speeds, loads and air-fuel ratios. Both Compression and Spark ignition heat release models are available. Port fuel and direct injection are also supported.

      The flow though the engine block is dictated by the valve geometry and opening characteristics and the piston-cylinder assembly model. Valve and spark timing effects on the fluid dynamics and combustion model mean that the engine performance can be investigated using this version of the library.

      This version of the Engine library is particularly suited to driveline nvh analysis, mount excitations, cranking and detailed friction modelling.

      In-cylinder pressure and temperature trace
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  • Powertrain Dynamics Library

    Vehicle model diagram
    Four Wheel Drive with automatic transmission
    Gearbox Model Diagrams
    Tip-In, Tip-Out simulation
    Capture the dynamics of the complete drivetrain system during driving manoeuvresQuickly build complex models with easy to use multibody components for the gears, shafts and jointsMake use of templates to build and reconfigure complete vehicle modelsIntuitive layout of subsystems with animation built-in to models


    The Powertrain Dynamics library is a Modelica library for modelling rotating MultiBody systems like automotive powertrains. It has been designed to provide a convenient modelling methodology and deliver efficient simulation of these complex systems. The models support the full design cycle using simple 1D representations for concept evaluation that easily evolve into detailed MultiBody models for detailed analysis. Animation is included in all the parts to aid understanding of the system dynamics. The library uses standard Modelica connectors and is compatible with all the other Automotive libraries available for Dymola.

    Key Features
    Library Contents
      • Detailed powertrain modelling with efficient simulation as a mulitbody system.
      • Includes engine, transmission, driveline and chassis models for complete vehicle simulation.
      • Build complex mechanical systems from individual elements such as bearings, shafts, gears, clutches, joints and mounting systems.
      • Evaluate 3D gear mesh forces, bearing loads and losses.
      • Shafts with a large number of linear and nonlinear compliance characteristics.
      • Longitudinal chassis models with Pacejka tyre slip and simple suspension with pitch and bounce.
      • Compatible with Vehicle Dynamics library, Engines, Powertrain and SmartElectricDrives libraries.
      • 3D Effects (torque reactions, gyroscopic effects etc.).
      • Faster simulation performance than Standard multibody library.
      • Flexible implementation.
      • Highly configurable with wide range of component fidelity.
      Animation of a gear pair with forces
    • The library is applied in many different applications as follows:

      1. Vehicle performance, fuel economy and drivability assessment capturing the full motion of the powertrain
      2. Hardware specification – complete torsional characteristic of transmission and driveline
      3. Conceptual architecture design – efficiency studies
      4. Control system optimisation using detailed physical models of the complete vehicle
      5. Modal analysis of the powertrain* for predicting torsional excitation modes i.e. shuffle
      6. Shift quality and feel - detailed components for capturing the dynamics of the gear shifting system
      7. Powertrain-chassis interaction – PTDynamics is fully compatible with the Vehicle Dynamics library allowing the interaction between the chassis and powertrain to be analysed
      Four wheel drive vehicle modelled with PTDynamics library
    • Numerous packages of example systems and experiments are included throughout the library with all models including default parameters for quick application and understanding of powertrain modelling.

      Library Components



      Engine animation view

      Mapped based engine model for torque generation, emissions and fuel consumption calculation. Simple engine controllers also included for idle speed and fuelling control.


      Transmission model

      Torque converts, Retarders, shift mechanisms including synchronizers, detents and shift barrels. Powertrain mounts are included with various DOF’s and compliance characteristics.


      Driveline animation view

      Collection of examples and experiments assembled from examples models from the shafts, joints and differentials packages.


      Animation view of a engine, gearbox, driveline and chassis models

      Simple chassis with pitch, and roll Degrees of freedom as well as linear and pacejka tyre models are included for longitudinal dynamics. Various road definitions are also included.


      Clutch model

      Numerous components for modelling torque transfer in a wide range of coupling elements. Wet and dry Multi-plate, Cone, Band and dog elements are all included ranging from simple to complex geometry defined responses.


      Differential diagram

      Templates and examples of gear bearing and shaft arrangements for a wide variety of differential arrangements (open and torsen) including slip control devices.


      Gear models

      Gear mesh models with 3D force calculations with optional backlash, mesh stiffness and efficiency for spur and helical gears. Numerous planetary configurations are also included configurable for different levels of fidelity. Simple chain drive models are also included.



      Multibody models of a wide range of joints found within power transmission systems including constant velocity, universal and plunging joints.


      Shaft models

      Numerous options for uniform and composite shafts are included with a wide variety of torsional characteristics from rigid and simple linear to non-linear plastically deformable characteristics are included using a computationally efficient MultiBody approach.



      Linear systems analysis package with functions for natural frequency analysis and plotting.


      Brake system icon

      Simple disc brake models are included.


      Driver system icon

      Open and closed loop drivers available for drive cycle and simple source manoeuvres as well as specific TipIn and idiot start tests.

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  • VDL Motorsports Library

    Car with history
    Double Wishbone Suspension Options
    Car racing around corner with history
    Open wheel race car with double wishbone with pushrod suspension
    Sports Car with double wishbone suspension
    NASCAR modelled using VDL Motorsports Library
    Real-time MultiBody double wishbone suspension models with pushrod, pullrod or direct actuationUsed in various open-wheel racing series including Formula 1 and IndyCarSuitable for modelling any car with double wishbone suspensionUsed in NASCAR to provide MultiBody models of the race car deployed into all simulation tools


    The VDL Motorsports Library is a motorsport focussed extension of the Vehicle Dynamics Library. This library delivers components, systems and experiments that are specific to motorsport applications and is used by customers in Formula 1, NASCAR, IndyCar and other race series.

    The combined use of VDLMotorsports, other Modelica libraries and Dymola can fulfil an organisations desire to use the same vehicle model across the all parts of the engineering process including in the design office, for HIL testing, integrated in track side tools and in the driving simulator. This is because the same model can accurately predict vehicle behaviour and run in real-time without a need to significantly reduce its fidelity.

    VDLMotorsports is fully compatible with the Vehicle Dynamics Library, enabling the models to be used in the standard test rig and experiments from that library. The models and templates within the library are highly customisable and extensible, and in combination with multi-domain nature of Dymola, this makes a flexible modelling environment for the user.

    Key Features
    Open Wheel
    Sports Car
      • Double wishbone suspension models with either pushrod/pullrod or direct spring actuation.
      • Solid axle with truck arms and panhard rod.
      • Kinematic models with optional compliance in uprights, tie rods, anti-roll bar links, pushrods, inboard mounts.
      • The suspension mechanisms include a full range of adjustment shims, applied in a physically realistic manner by defining shim sizes.
      • All the models are optimised to run in real-time to support hardware, software and driver in the loop simulations
      • Setup calculation experiments give a convenient method for determining the adjustments required for a desired vehicle setup.
      • Pacejka tyre models which incorporate tyre pressure and aerodynamics effects.
      • A number of aerodynamic models are available to implement the body and wing aerodynamic effect on the chassis.
      • Additional experiments and sensors are provided to perform half car kinematics tests with the wheels fitted and quasi-static laptime calculations.
      Suspension Model Template
    • The VDL Motorsports Library provides a comprehensive collection of double wishbone suspension configurations for open-wheel racing applications such as Formula 1, IndyCar and similar vehicle configurations.  The models include options for pushrod and pullrod actuation with numerous rocker arrangements.

      The rocker arrangement models comprise combinations of ride springs, dampers, heave springs, monoshock, inerter and anti-roll systems as well as the rocker mechanism. These optimised suspension models enable real-time running without additional detailed work by the user.

      All the suspension models supplied in VDL Motorsports feature a full range of adjustments, which are implemented in a physically realistic manner by the addition of adjustable size shims.  The mechanisms also include spring preload adjusters. Setup calculation experiments will automatically determine the adjustments and preloads necessary to achieve a specified setup target, these are available for both half car and full chassis models.

      Geometry records are used in the suspension models for convenient parameterisation through a single interface. The library provides a simple tool to easily allow the setup results to be stored in a new record. This method allows the user to quickly change the geometry and setup applied to a vehicle model.

      Open wheel race car with double wishbone with pushrod suspension
    • The VDLMotorsports library has been extended to include support for NASCAR providing all the same features found in the original open-wheel and sports car version.

      The front suspension model is a direct acting double wishbone suspension model using the same optimised real-time capable model as the other versions of the library.

      The rear truck arm suspension model has been developed and optimised to be real-time capable. This has required the development of new efficient joint combinations to model the over-constrained rear suspension that relies on the deflection of the links and bushes to work.

      The library includes generalised setup procedures with methods to enable the customisation of the experiments to tailor them to match your own teams process. These experiments allow the tuning of corner weights, frame heights and wheel angles (toe and camber).

      NASCAR Detail view
    • For sports car racing and high performance applications the library provides double wishbone suspension configurations with direct acting springs, dampers and anti-roll bars.

      All the suspension models supplied in VDL Motorsports feature a full range of adjustments, which are implemented in a physically realistic manner by the addition of adjustable size shims.  The mechanisms also include spring preload adjusters. Setup calculation experiments will automatically determine the adjustments and preloads necessary to achieve a specified setup target, these are available for both half car and full chassis models.

      Geometry records are used in the suspension models for convenient parameterisation through a single interface. The library provides a simple tool to easily allow the setup results to be stored in a new record. This method allows the user to quickly change the geometry and setup applied to a vehicle model.

      This library provides vehicle body models specifically for motorsports applications, which include ballast locations and aerodynamics models with separate body, front and rear wings. The aerodynamic examples use either single coefficients or lookup tables for convenient parameterisation, but the templates and components can be used and modified should a more complex aerodynamic model be required.

      Sports Car with double wishbone suspension
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  • Simulator Library

    Dymola and rFactor Pro Integration


    The Simulator library for Dymola is used to interface Modelica Vehicle Dynamics models built with the VDLMotorsports library with rFactor Pro so that they can be used in Driver in the loop (DiL) simulators.  The VDLMotorsports library is used to create the full vehicle physics model and this is then exported using the Dymola Source Code Export feature and compiled into applications that are run within PTWinSim or vTAG environments. The PTWinSim and vTAG applications interface with rFactor Pro using plugins that are developed by Podium Technologies. Using the VDLMotorsports and Simulator libraries, a Dymola multibody vehicle dynamics model can be quickly and conveniently compiled for use in driver-in-the-loop simulators.
    Key Features
    Simulator Interface
    Build Function
      • A Simulator interface template is provided that can interface with the rFactor Pro plugins. The user simply plugs their own vehicle dynamics model into this interface.
      • Includes support for collision handling, tyre contact using the standard and high-definition surface options, track interface for chassis contact and the driver controls with feedback.
      • Telemetry data can be customised and streamed from the model via PTWinSim and vTAG so that it can be viewed in Altas, Gredi or a similar data capture tools.
      • A Build function exports and builds the simulation models into PTWinSim and vTAG applications in one step.
      • Advanced real-time solver and optimisation features are selectable in the Build function, this assists the user in generating a model efficient enough for real-time simulation.
      • Debugging options in the Build function allow for examining the simulation in more detail.
      rFactor Pro Interface Layout
    • rFactor Pro requires a large number of input and output signals to be able to run a third party vehicle model as part of a Driver-in-the-loop simulator. The Simulator interface template contains these required signals in a reusable Modelica template. The user simply extends this Modelica model and replaces the vehicle model with their own vehicle dynamics model. Before exporting the model from Dymola it can be run in a test environment within Dymola.  This is used to debug the model and ensure that it is working correctly and runs at a suitable rate for use with rFactor Pro.  After it passes the tests, the model is built into an App to be used in vTAG/PTWinSim to interface with rFactor Pro. The Dymola Simulator interface includes collision handling, the interface with the motion platform, the wheel to track interface, the atmosphere interface, a ground interface, the driver input interfaces as well as the other signals that are required by rFactor Pro. The vehicle model has to be able to run in real-time so the models provided have been designed to be efficient and avoid unnecessary events. This is delivered by the VDLMotorsports library which is an extension to the standard Dymola Vehicle Dynamics Library tailored for real-time simulation and motorsport applications.  The approach enables the same vehicle dynamics model to be used for offline experiments such as kinematic tests, 7 post rig and dynamic driving events as well as for the Driver-in-the-loop environment
      rFactor Pro Simulator Interface Model
    • A function in the Simulator library is used to export the Modelica models from Dymola and compile the vehicle dynamics models into PTWinSim or vTAG applications in one step. The user selects the model to be exported and configures the settings for inline integration, step size and the advanced real-time simulation flags available in Dymola. In addition the user can choose between compiling a vTAG or PTWinSim App and specify the names, app number and version number to be used.  There are also a number of debugging options available such as turning on profiling or sending the internal states of the solver to output signals from the model. Once exported, the model parameters can be edited in Gredi or System Monitor.  This enables the suspension setup to be changed without requiring the model to be recompiled.
      Build Function and Library
  • FlexBody Library

    Animation of excavator with flexbody model used for the boom
    FlexBody used as part of a suspension model


    The FlexBody library enables you to build complete mechanical models combining flexible structures and rigid bodies. Using features of the Finite Element analysis tools Nastran, Genesis or Abaqus, large, complex Finite Element models can be reduced to simpler models consisting of a small number of boundary nodes, or attachment points, and frequency modes. The reduced models are read in to Dymola and define the flexible component which can be used as part of a Modelica system model. This approach enables the dynamics of the structure to be coupled to the behaviour of the complete system.

    Key Features
    Modelling Approach
      • Enables the creation of complete mechanical models combining flexible structures and rigid bodies.
      • Standard Finite Element analysis methods and tools are used to reduce the FE models and define flexible bodies for use in Dymola.
      • Reads the standard output files produced by Nastran, Genesis and Abaqus.
      • Compatible with the Modelica MultiBody library and other Modelica libraries based on this including the Vehicle Dynamics library.
      • Supports Dymola 2012 FD01 and later
      FlexBody Library
    • Nastran, Genesis and Abaqus include methods for model reduction known as Component Mode Synthesis or Craig-Bampton reduction. These transform the detailed Finite Element models in to more efficient representations for use in dynamics. This transformation reduces the models from 100,000’s degrees of freedom to a much smaller number of degrees of freedom at defined boundary nodes, or attachment points, and a number of frequency modes of the structure.

      The reduced models are defined by the Finite Element tools to represent small displacements of the boundary nodes. To capture the true dynamics of the body the deflections of the structure are super-imposed on the motion of a floating rigid reference frame that captures the large displacements and rigid body modes of the structure.

      The reduced models are then read in to Dymola using the FlexBody library. This then defines a flexible component which can be used as part of a Modelica system model and is compatible with the MultiBody library in the Modelica Standard Library. This approach enables the dynamics of the structure to be coupled to the behaviour of the complete system.

      Importing FEA for use in a systems models
    • The typical application areas for the FlexBody library include robotic arms, large machines such as excavators and cranes, and automotive components like suspension arms, brakes and folding roof mechanisms.  The library is useful in any situation where the response of the structure has a significant impact on the overall system dynamics.  The library has been written to be compatible with the Modelica MultiBody library which is used as the basis for all other MultiBody applications such as Vehicle Dynamics.

      The model on the right uses a FlexBody component to model the lower control arm in the double wishbone suspension.  The suspension is then placed in a kinematics and compliance (KnC) test rig and the forces (red) and torques (green) acting at the wheel centre are applied.  In this case measured road load data is applied to the wheel hub and the response of the suspension can be assessed.

      By including the structural compliance in the control arms the effect on the toe and camber angles and the reactions in to the vehicle body can be assessed.  In addition the load cases for further finite element analysis (FEA) can be determined and the targets for the stiffness of the control arms can be refined.

      Model diagram using a FlexBody component to model a suspension control arm
  • XML Reader Library

    Quick overview of how the XML Reader library works


    The XMLReader library provides models and functions for extracting data from XML files. Real and String scalars and matrices can be extracted and used to set model parameters.

    Reading parameters from an XML provides a way to log the setup of a model and allows for easy modification of model parameters. Efficient batch simulation is supported as the model does not have to be recompiled to read any changes in the XML file, any XML changes will be read during initialisation of the model.

    Key Features
    Reading data
    Document wizard
      • Reads parameter values from XML documents directly into a Modelica model.
      • A wizard is provided to help configure the XML reader so that it understands your document format.
      • Reads both Real and String values.
      • Reading of matrices in delimited, Matlab ® syntax and other formats is supported.
      • Reading of XML matrices into .mat files, for efficient handling of tables.
      • Able to efficiently handle large XML documents.
      • Supports Dymola 2012 FD01 and later.
      Overview of the XML reader used to get parameters for a model
    • To read a value from the XML document and return it as a real scalar in Modelica, the user simply calls a function called readReal that exists within the Document model that has been added to the system model. This readReal function is used to set parameters to be equal to the values in an XML file.

      Other functions are supplied for extracting String values and for extracting Real and String matrices. A number of different matrix formats are supported including delimited matrices and the Matlab&Reg; matrix syntax and more.

      Matrices can also be read into .mat files for efficient use in the Table blocks.

      Reading xml data using the XML Reader library
    • Each model requires an XML document that defines what XML file is to be read and the format of the XML file. A wizard is supplied that helps generate the document model that describes the format used in the XML file.

      This wizard searches through the XML document and finds the possible formats where componentName is a component and parameterName is a parameter and allows the user to select which of these formats is the desired format.

      Wizard used to define XML data models
  • fmi-blockset - small

    The FMI Blockset supports running FMI compliant models in both Simulink and Microsoft Excel.

    FMI Blockset for Simulink

    The FMI Blockset for Simulink® provides support for the Functional Mock-up Interface (“FMI”)  open standard in Simulink.  This means that models that are compiled by third party tools such as Dymola, CATIA DBM and many more can be imported and used in Simulink.  Models that are compiled to be compatible with this standard are known as Functional Mock-up Units (“FMU”). Simulink model containing and FMI block and associated editor The FMI standard defines two interfaces: one for model exchange; and one for co-simulation. The FMI Blockset currently supports the FMI 1.0 Co-simulation interface and the FMI 2.0 Model Exchange and Co-simulation interfaces. When using the Co-simulation interface, this means that the solver built in to the FMU is used to simulate that model and the Simulink solver is used to simulate the Simulink part of the system with the two systems exchanging data at discrete times. The advantage of this is that appropriate solvers can be used for both parts of the model improving the overall simulation performance. When using the Model Exchange interface, the Simulink solver is used to handle the complete model i.e. the FMU equations and the Simulink model.  This allows variable step solvers to be used and has the advantage that a single solver is used for the entire model.

    FMI Blockset for Excel

    The FMI Blockset for Excel allows FMU's that are compliant with the FMI 2.0 Co-simulation interface to be simulated from within Microsoft Excel®.  Using this add-in enables an FMU to be selected and configured within Excel using the FMI Blockset interface.  After making a number of parameters available in Excel, multiple cases can be configured and simulated to run parameter sweeps, sensitivity studies, etc.  For each simulation case, a new spreadsheet is added to the Excel workbook to capture the results from that simulation. FMI Blockset For Excel

    Parameter Editors

    Where structured naming is used within the FMU, this is used by the editor in to generate the parameter structure as shown above.  Each group of parameters is denoted by a folder and each parameter is shown by name with an icon representing its base data type (Real, Integer, Boolean, Enumeration and String). Clicking on a parameter name shows the details contained in the FMU and allows the value to be modified.  If unit conversions are defined in the FMU these are also available.  For vector and matrix parameters an Edit button is shown that gives access to an appropriate editor with a plot of the data.  Through this editor new maps can be loaded from csv and Matlab binary files provided the dimensions of the vector or matrix are not changed as these are fixed in the FMU. Matrix Editor

    Load and Save Parameter Sets

    The configuration and current parameter settings can be saved from the editor in XML format.  This format is defined in the FMI standard.  When saving the current configuration as a setup, a new XML file is created outside the FMU rather than modifying the model descripton file provided in the FMU.  These saved setups can include additional notes documenting the changes that have been made from the original FMU parametisation. You can also load setup’s from these XML files with the editor performing checks to make sure that the setup you are loading matches the FMU you have currently loaded.

    Further information

    For further details on the FMI Blockset for Simulink you can download this brochure.  If you would like to try out the FMI Blockset then please contact sales [at]