Visualizer for large-scale and interactive ray-tracing of neurons
C++ CMake Python JavaScript Cuda C Other



One of the keys towards understanding how the brain works as a whole is visualisation of how the individual cells function. In particular, the more morphologically accurate the visualisation can be, the easier it is for experts in the biological field to validate cell structures; photo-realistic rendering is therefore important.

The Blue Brain Project has made major efforts to create morphologically accurate neurons to simulate sub-cellular and electrical activities, e.g. molecular simulations of neuron biochemistry or multi-scale simulations of neuronal function. Ray-tracing can help to highlight areas of the circuits where cells touch each other and where synapses are being created. In combination with ‘global illumination’, which uses light, shadow, and depth of field effects to simulate photo-realistic images, this technique makes it easier to visualise how the neurons function.

Brayns is a minimalistic visualiser that can perform ray-traced rendering of neurons. It provides an abstraction of the underlying rendering engines, so that the best possible acceleration libraries can be used for the relevant hardware. (

To keep track of the changes between releases check the changelog.





The following platforms and build environments are tested:

  • Linux: Ubuntu 16.04, RHEL 6.8 (Makefile, x64)

The API documentation can be found on

Building from Source


In order to ease the application compilation process, we recommend using the following tree structure:

- src
  +- ispc-v1.9.0-linux
  +- OSPRay
  +- BRayns

Intel ISPC compiler

Download and extract ISPC compiler 1.9.0 archive.


Clone embree in the same folder level as ISPC compiler

  git clone
  mkdir embree/Build
  cd embree/Build
  cmake .. -DCMAKE_INSTALL_PREFIX=<Brayns_installation_folder>
  make install


Clone OSPRay in the same folder level as ISPC compiler

  git clone
  mkdir OSPRay/Build
  cd OSPRay/Build
  export embree_DIR=<Brayns_installation_folder>
  cmake .. -DOSPRAY_USE_EXTERNAL_EMBREE=ON -DCMAKE_INSTALL_PREFIX=<Brayns_installation_folder>
  make install


  git clone
  mkdir Brayns/Build
  cd Brayns/Build
  cmake .. -DOSPRAY_ROOT=<Brayns_installation_folder> -DEMBREE_ROOT=<Brayns_installation_folder> -DCMAKE_INSTALL_PREFIX=<Brayns_installation_folder>
  make install

A number of dependencies are optional, and are related to some specific Brayns features:

Enable/Disable assimp supported mesh file loader (.obj, .ply, etc.)


Enable/Disable Brion supported morphology file loader (.h5, .swc, BlueConfig, CircuitConfig)


Enable/Disable Deflect for streaming to Tide, the Tiled Interactive DisplayWall environment.


Enable/Disable ImageMagick image loading


Enable/Disable HTTP/REST interface.

Servus, ZeroBuf, Lexis, LibJpegTurbo and ZeroEQ. See documentation for REST API details.


Running Brayns viewer

export PATH=<Brayns_installation_folder>/bin:$PATH
export LD_LIBRARY_PATH=<Brayns_installation_folder>/lib:$LD_LIBRARY_PATH

Running Brayns off-screen service

export PATH=<Brayns_installation_folder>/bin:$PATH
export LD_LIBRARY_PATH=<Brayns_installation_folder>/lib:$LD_LIBRARY_PATH

Known Bugs

Please file a Bug Report if you find new issues which have not already been reported in Bug Report page. If you find an already reported problem, please update the corresponding issue with your inputs and outputs.