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MotionSolve Reference Guide
This manual provides a detailed list and usage information regarding command statements, model statements, functions and the Subroutine Interface available in MotionSolve.
The Subroutine Interface for MotionSolve
Types of User-Written Subroutines
To facilitate the creation of solver extensions, MotionSolve provides you with a well-defined interface and a well-defined methodology for creating user subroutines.
Utility Subroutines
Utility subroutines are functions that are useful when writing user-written subroutines.

Welcome
What's New
View new features for MotionSolve 2025.1.
Overview
MotionSolve^® is an integrated solution to analyze, evaluate, and optimize the performance of multibody systems.
Tutorials
Discover MotionSolve functionality with interactive tutorials.
MotionSolve User Guide
MotionSolve is a system level, multibody solver that is based on the principles of mechanics.
MotionSolve Reference Guide
This manual provides a detailed list and usage information regarding command statements, model statements, functions and the Subroutine Interface available in MotionSolve.
- Notation and Syntax
- Creating MotionSolve XML Files
- Writing Custom Elements for MotionSolve
- Writing Custom Functions for MotionSolve
- Supported Versions - Third Party Software
- Command Statements
- Model Statements
- Functions
- The Subroutine Interface for MotionSolve
  - User Subroutines and MotionSolve
  - System Requirements
  - Types of User-Written Subroutines
    To facilitate the creation of solver extensions, MotionSolve provides you with a well-defined interface and a well-defined methodology for creating user subroutines.
    - Driver Subroutines
      Driver subroutines are user-written subroutines that allow you to create and execute your own types of analyses. These analyses are typically composed of level analyses that are provided to you by MotionSolve.
    - Utility Subroutines
      Utility subroutines are functions that are useful when writing user-written subroutines.
      - Analysis Control Subroutines
        Analysis control subroutines are built-in subroutines provided by MotionSolve that allow a user-written subroutine to perform various types of analysis, generate output and modify the model defined in the XML input file.
      - Data Access Subroutines
        Data Access subroutines are built-in subroutines provided by MotionSolve that allow a user-written subroutine to access model parameter or state information.
    - Modeling Subroutines
      Modeling subroutines are user-written subroutines that allow you define the run-time behavior of a modeling element via a user subroutine.
- ADM/ACF Entities
- NLFE Statements
- msolve API Statements

Utility Subroutines

Utility subroutines are functions that are useful when writing user-written subroutines.

There are three types of Utility subroutines:

Data Access subroutines, which are built-in subroutines provided by MotionSolve that allow a user-written subroutine to access model parameter or information state.
Analysis control subroutines, which are built-in subroutines provided by MotionSolve that allow a user-written subroutine to perform various types of analysis, generate output and modify the model defined in the XML input file.
General utility functions that aid in the creation of user-subroutines.

These subroutines are packaged within MotionSolve and their interface is documented, so that you can simply use the functions you need. You need not recreate these.