OSPRay for Hydra

OSPRay interactive rendering plugin for USD Hydra

Rendering of the ALab scene using OSPRay for Hydra. The ALab asset is Copyright 2022 Animal Logic Pty Limited. All rights reserved.

OSPRay for Hydra

OSPRay for Hydra is an open source plugin for Pixar’s USD to extend the Hydra rendering framework with Intel® OSPRay. OSPRay for Hydra enables interactive, path traced rendering by utilizing OSPRay’s renderers and Intel® Open Image Denoise. OSPRay for Hydra and OSPRay are released under the permissive Apache 2.0 license.

As part of the Intel oneAPI Rendering Toolkit, OSPRay is highly-optimized for Intel® CPU architectures ranging from laptops to large-scale distributed HPC systems. OSPRay for Hydra leverages the Intel® Rendering Framework to deliver interactive rendering for large-scale models at high levels of fidelity, as demonstrated at SIGGRAPH 2018 using over 100GB of production assets.

Support and Contact

OSPRay for Hydra is still in beta, with new features and existing issues being worked on regularly. USD is also under active development and is often fast changing. We tag the OSPRay for Hydra releases to match specified USD releases, but cannot always anticipate all of the changes and resulting issues for users. Please report any issues you may run into to our issue tracker. We always welcome suggestions and especially pull requests!

Building OSPRay for Hydra

OSPRay for Hydra source is available on GitHub at OSPRay for Hydra. The master branch is typically the most stable branch and contains tagged releases.

Tags are of the form hdospray-vx.x.x-usdvx.x.x, with vx.x.x being the release of OSPRay for Hydra and usdv being the version of USD it is built against. This is required due to the frequently changing internals of hydra.

Currently OSPRay for Hydra is regularly tested on Linux Arch. MacOS support in USD is experimental, but we often test against it. Windows support of USD is also experimental, but we have not tested OSPRay for Hydra with it.

Prerequisites

If using the superbuild, the only dependencies are: - c/c++ compiler (gcc 6.3.1+) - cmake 3.1.1+ - python (3.7.x+ recommended), with PySide/PySide2 and PyOpenGL. ‘pip install PySide2 PyOpenGL’ may work

If you are building standalone, you will need: - USD 22.08, 21.08, or 20.08 - For a full list of USD dependencies, see the USD page. - OSPRay 2.10.0 - We recommend using ospray’s superbuild to build dependencies such as embree, ospcommon, and openvkl. OpenImageDenoise can also be enabled through superbuild. - OpenImageIO 1.8.17

Optional Dependencies

• Houdini SDK (tested against 18.5 and 19.0). To use, enable SUPERBUILD_USE_HOUDINI in superbuild.
• OpenImageDenoise
  • Open Image Denoise needs be be enabled in the OSPRay build.

Superbuild on Linux/MacOS

OSPRay for Hydra contains a cmake superbuild script that builds external dependencies for you and is the recommended way of building OSPRay for Hydra. Alternatively, instructions for manually building each component is also given. Currently, USD 21.08 is the default to match Houdini, but this can be changed to 20.08 or 22.08 by setting the USD_VERSION in cmake.

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=<install_dir> ../scripts/superbuild/ (or use ccmake to specify option through gui)
cmake --build . -j <numthreads>

By default, all install files will be installed into /install. A setup script can then be called to set paths:

source <install_dir>/setup_hdospray.sh
usdview <usdfile> --renderer OSPRay

Manual Compiling USD on Linux/MacOS

To build USD, see the USD GitHub site. If you wish to use usdview, you must also enable imaging and python.
The options and compilers used can vary from our example, but make sure that TBB use is consistent across your build of USD, OSPRay for Hydra, and OSPRay. The command we use for building USD manually is:

python <USD_SOURCE>/build_scripts/build_usd.py --python --usd-imaging --openimageio <USD_BUILD_DIR>

To set TBB explicitly, go to <USD_BUILD_DIR>/build/USD and set TBB libraries and include directories using cmake.

Compiling OSPRay on Linux/MacOS

You can use the distributed binaries of OSPRay or build it yourself. We recommend using the OSPRay superbuild system according the instructions listed on github. Make sure that TBB is the same used by USD. You can force using system TBB using the superbuild by going to <OSPRAY_BUILD_DIR>, and setting the cmake variable DOWNLOAD_TBB to OFF.

Compiling OSPRay for Hydra on Linux/MacOS

OSPRay for Hydra plugin uses a CMake build system which links in USD and builds externally from the USD source directory, but configures CMake as if it were inside the USD repository in order to build the plugin using USD internals. It must therefore be built against a version of USD that matches OSPRay for Hydra, which is specified in the versioning tag of OSPRay for Hydra.

• Download/clone the git repo for OSPRay for Hydra

  $ git clone https://github.com/ospray/hdospray.git
  

• Create a build directory and call CMake

  $ cd hdospray
  $ mkdir build
  $ cd build
  $ ccmake ..
  

• Set CMAKE_INSTALL_PREFIX to the installation directory of USD.

• Set pxr_DIR to the install directory of USD which contains pxrConfig.cmake

• Set ospray_DIR to the directory containing your osprayConfig.cmake

  • This can be found in the root directory of the distributed binaries or if you are building and installing from source it can be found in <install>/lib/cmake/ospray-\*/

• Set openvkl_DIR to install directory of OpenVKL. These will be the same as ospray_DIR if you downloaded the OSPRay binaries, or in OSPRay’s superbuild directory under install/openvkl/lib/cmake/openvkl*.

• Set rkcommon_DIR to install directory of rkCommon. These will be the same as ospray_DIR if you downloaded the OSPRay binaries, or in OSPRay’s superbuild directory under install/rkcommon/lib/cmake/rkcommon*.

• Set embree_DIR to install directory of Embree. These will be the same as ospray_DIR if you downloaded the OSPRay binaries, or in OSPRay’s superbuild directory under install/embree/lib/cmake/embree*.

• Compile and install OSPRay for Hydra

  $ make -j install
  

The plugin should now be in <usd install directory>/plugin/usd/hdOSPRay

Compiling OSPRay for Hydra on Windows

We do not currently test on Windows, but all dependencies are.

Documentation

Running

Once built, the plugin code should be located in your usd install directory under plugin/usd/HdOSPRay. Run usdview <scenefile> and select view->Hydra and then Renderer->OSPRay.

OSPRay can be set to the default renderer by either

• Setting the HD_DEFAULT_RENDERER environment variable

  $ export HD_DEFAULT_RENDERER=OSPRay
  

• Specifying --renderer OSPRay as a command line argument to usdview

Environment variables

Most of these options are also exposed through the usdview GUI under Hydra Settings.

• HDOSPRAY_SAMPLES_PER_FRAME

  Number of samples per pixel.

• HDOSPRAY_SAMPLES_TO_CONVERGENCE

  Will progressively render frames until this many samples per pixel, then stop rendering.

• HDOSPRAY_LIGTH_SAMPLES

Number of light samples at every path intersection. A value of -1 leads to sampling all light sources in the scene. Does not affect scivis renderer.

• HDOSPRAY_AMBIENT_OCCLUSION_SAMPLES

  Number of ambient occlusion samples to compute per pixel. Does not affect path tracer.

• HDOSPRAY_CAMERA_LIGHT_INTENSITY

  Globally modify the intensity of all lights.

• HDOSPRAY_USE_PATH_TRACING

  Use Monte Carlo path tracer instead of faster Whitted-style renderer.

• HDOSPRAY_MAX_PATH_DEPTH

  Maximum ray depth. Will affect the number of diffuse bounces as well as transparency.

• HDOSPRAY_USE_SIMPLE_MATERIAL

  Use a simple diffuse + phone material instead of principled material.

• HDOSPRAY_INIT_ARGS

  Specify arguments sent on to OSPRay for initialization. e.g. enable MPI.

• HDOSPRAY_PIXELFILTER_TYPE

  The type of pixel filter used by OSPRay: 0 (point), 1 (box), 2 (gauss), 3 (mitchell), and 4 (blackmanHarris).

• HDOSPRAY_FORCE_QUADRANGULATE

  Force Quadrangulate meshes for debug.

• HDOSPRAY_USE_DENOISER

  If built in, enable the denoiser

Features

• Denoising using Open Image Denoise
• Distributed multi-node rendering over MPI
• UVTextures
• Pixel Filters
• usdLux lights: disk, distant, dome, quad, sphere.
• Triangle meshes
• Quad meshes
• Subdivision surfaces
• Ray traced shadows and ambient occlusion.
• Path tracing
• Physically-based materials
• Principled shader (similar to Disney BSDF shader)

News, Updates, and Announcements

• Dec 2, 2022: Version v0.11.0

  - Texture Transforms
  - UDIM textures
  - Texture channel masks
  - Tonemapper settings
  - Interactive rendering reworked
  - Bug fixes
  

• Sep 20, 2022: Version v0.10.1

  - USD 22.08 support. 21.08 is still default in superbuild for houdini. 
  - Golden image tests added
  - Github actions workflow added for CI
  - Bug fixes
  

• June 10, 2022: Version v0.10

  - USD 21.08 support, which is now the default in superbuild.  20.08 still supported if enabled.
  - Instance, Element, and Primitive ID buffers added
  - Testing added with image comparisons
  - Added facevarying texture and color support.
  

• Feb 15, 2022: Version v0.9

  - Adding depth AOV
  - Adding normals AOV
  - Additional material parameters
  - Fixing generic texcoord naming
  - Update to OSPRay 2.9
  - Adding cylinder light
  - Adding camera depth of field
  - Minimal support for geomsubset materials
  - Ptex support currently deprecated in OSPRay.  Will be re-enabled upon OSPRay module_ptex release.
  

• August 24, 2021: Version v0.8

  - Update to USD 20.08.
  - Houdini support.
  - Color buffer AOV support.
  - Superbuild script added.
  - Added camera light visibility flags.
  - Add thin materials.
  

• May 28, 2021: Version v0.7

  - Update to OSPRay 2.6.0
  - Ptex support re-enabled.
  - Numerous light and material updates. Added disk lights.
  - Toggle for light enabled vs visible.
  - Animation update fixes.
  - Support for curves.
  

• October 12, 2020: Version v0.6

  - Update to OSPRay 2.4.0
  - Added support for opacity textures.
  - Added adaptive view port scaling. The viewport is
    now scaled to reach a given interactive framerate (e.g., 10fps).
  - Fixed some bigs with animated shapes (e.g., ARKit data sets).
  - Added support to toggle the visibility of light sources and shapes.
  

• July 31, 2020: Version v0.5

  • Update to OSPRay 2.2.0.
  • Added UsdLux light support.
  • Asynchronous rendering.
  • Dynamic resolution for greater interaction.
  • Pixel Filters.
  • Subdivision surfaces interpolation mode fixes.

• June 15, 2020: Version v0.4

  • Update to OSPRay 2.1.0.
  • Update to USD 20.05.

• September 15, 2019: Version v0.3

  • Subdivision surfaces support.
  • GUI options for usdview.
  • Various bug fixes.

• April 30, 2019: Version v0.2.2

  • Various bug fixes.
  • OSPRay version updated to 1.8.5.
  • CMake targets.
  • Added animation support.

• Mar 7, 2019: Version v0.2.1

  • Bug fixes.
  • Ptex updates.
  • Documentation.

• Feb 28, 2019: Version v0.2.0

  • Initial Beta release version 0.2.0 is now available on the HdOSPRay GitHub page. This replaces the previous repository and versioning which was on my personal github account.