Download BioGears

We are releasing the BioGears Physiology Engine and Common Data Model under the Apache 2.0 license.

You can use BioGears as a stand-alone application or integrate BioGears into your training and immersive learning technologies. We provide comprehensive documentation, including an SDK that provides detailed tutorials and step-by-step information to help our end user groups: simulation content developers, biomedical modelers, MedSim technology integrators, and researchers/ educators.

Over the next year of the project we will continue to add physiology systems and functionality to BioGears. We look forward to hearing from you and encourage feedback from our users who have downloaded BioGears 7406 times!

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Toolkit DMG SDK Source Code Documentation Verification

Official Release

Our latest deployment is still in a beta phase, and is intended to be an intermediate release to showcase the capabilities of the BioGears® Physiology Engine. The current version of the software includes examples of all types of engine interfaces, but does not include all of the functionality or physiologic systems that will be present in the final product. This version of the software is meant to elicit feedback and enhance community involvement in establishing end product expectations.

Release Notes 6.3.0

The latest deployment includes the following notable updates:

  • General bug fixes, system improvements, and tools/solver improvements
  • Fasciculation patient event flags
  • Updated sweat methodology (fixes to ions lost in sweat)
  • Updated substance and compound infusion functionality
    • Added Ringers lactate and updated
    • Saline compound ion concentrations corrected
    • Hardened implementation
  • MuscleMass new patient data request
    • Muscle catabolism patient flag
  • Added dehydration condition
    • Implemented as scalar 0to1 representing fractional total body water lost
    • Fluid removed from patient compartments
    • Updated patient flag for event and track body weight change (validated)
    • Added totalbodyfluidVolume as data request
    • Updated patient weight as a function of condition
  • Added starvation condition
    • TimeSinceMeal determines how long since the patient's last meal
    • Scales internal nutrient storages from validated starvation data
    • Removed ConsumeMeal condition, now replaced by starvation condition
    • Validated blood concentrations for ketones, glucose, and amino acids
    • Updated patient weight as a function of condition
  • Intracellular ion transport
    • Model uses membrane potential (see Tissue Methodology for details)
    • Michaelis coefficient could support more ion regulation in the future
    • Gated ion transport allows for differences between intra/extracellular spaces
  • COPD now supports elevated anaerobic metabolism
  • Ion transport model in the small intestine
  • Updated drug library so all drugs support an effects site transport rate
  • Diabetes type 1 and type 2 conditions
    • Insulin resistance and insulin production effects
  • Hemorrhage action now initialized with a 0-1 severity and a location (MCIS SDK example still exists)
  • New drug Vasopressin
  • New drug classifications in the CDM for better grouping in-code
    • Include anesthetic, sedative, opioid, and reversal agent
    • More grouping in future work

(Interested in a previous Version?)

Known Issues

The following are known issues with the current version of the software:

  • Lack of a full sympathetic/parasympathetic nervous system
  • Extravascular fluid exchange model is incomplete
  • Peripheral resistance currently does not scale with core temperature
  • Only tested a simulation up to 24 hours in length (No Sleep model)
  • The Java GUI (Toolkit) doesn't support the RenalSystemValidation scenario


We are developing BioGears with various user groups in mind. We provide design decisions and functionality in several deployment packages to cater to each user group.

The packages listed below are available for Windows, Mac, and Ubuntu Linux. We recommend at least 1 GB of RAM for all downloads.

  • The BioGears library (run via the console executable) has a process footprint of approximately 15 MB.
  • The BioGears GUI and graphing scripts can run up to 512 MB of process memory due to the Java Virtual Machine (JVM) and graphing large amounts of data.


We created a suite of tools to drive the BioGears Engine. This Toolkit is intended for users (e.g., researchers, educators, or curious individuals) who wish to execute BioGears and view the physiological effects of the patient. These tools will create and plot a time-based, tab-delimited file of calculated physiological outputs.

The Toolkit unzips about 15 MB of files. We recommend having at least 1 GB of available disk space.

  • The result files generated from the command line executable and GUI average 20 MB.
  • Graphed results file from the GUI or graphing script can generate file sets of several hundred MB.

See the Toolkit for details of the tools and how to use them.

Development Kit

We created a software development kit (SDK) to help developers integrate the BioGears Engine into software applications. This SDK provides pre-built libraries and headers, as well as examples of programmatically using the provided interfaces. The provided application programming interfaces (APIs) provide full control over the engine to execute various actions and retrieve a wide range of calculated physiological outputs

The SDK unzips around 200 MB of files. Dynamic execution of the engine does not produce any files.

The Software Development Kit provides details of the interfaces and how to use them.

Source Code

The full BioGears source code is available for users to view and review implementation, contribute improvements, and integrate or replace models for use with the BioGears systems.

The source unzips around 350 MB of files. We recommend having at least 5 GB of disk space dedicated to building BioGears. The Source Code contains all code, scripts, data, and documentation to rebuild BioGears.

Scenario Baselines

We include scenarios and baselined results used for verification and validation. As changes are implemented in the code base, doing a comparison after making modifications shows how changes to the scenario files or code itself manifests in BioGears system data. This data is used extensively to validate each system individually, as well as the combined effects of insults and interventions—see the Methodology Reports for more details. The scenarios output requests match the columns in the results file; we recommend that you do not modify these scenarios.

The complete data set unzips around 2 GB of files. Execution of all scenarios provided can generate up to 20 GB of results data.