Rendering With Houdini

In this tutorial, we present a method to render Golaem simulations with Houdini. The really big advantage of this method is that it avoids baking out geometry from Maya, interacts with Houdini FX and can be rendered using Mantra.

Supported Versions

Notice that you need the following versions of software for this process to work:

  • Golaem 7.1 and above
  • Houdini 17.5 and above. Please check the Release Notes

Workflow

The figure below details the workflow of the render of Golaem simulations with Houdini.

Setup in Maya

Setup the Simulation In Maya

Create your Crowd Simulation within Maya using Golaem . In our example we will use the locomotion scene from the Golaem Crowd Samples. Once the simulation is done, open the Simulation Exporter to export the Simulation Cache. Once the Simulation Cache will be exported, a Simulation Cache Library File (.gscb) will be created in the same directory than the Simulation Cache. It is also possible to add the exported simulation to an existing Simulation Cache Library File using the Library Tool.

The Simulation Cache Library File contains the useful information about exported simulations such as the export directory, the Character Files used...

Setup Houdini

A few steps must be undertaken for Houdini to be able to load and render with the Golaem plugin.

Installing the Golaem For Houdini Plugin

The Golaem for Houdini plugin can be found in its own section on the Golaem Download Page and is made of four directories and one .uplugin file:

Adding Golaem For Houdini to your Environment

Then, for Houdini to be able to find the Golaem For Houdini Plugin, its path needs to be added to the predefined HOUDINI_DSO_PATH environment variable and a couple of others. There are many ways to add a path to an environment variable, however for our test, we chose to create a bat / shell file to launch Houdini with the correct environment.

Linux

#!/bin/sh
# Set Environment Variables for Golaem

export GOLAEM_INSTALL_PATH=/home/golaem/Golaem-7.1-Houdini17.5
export LD_LIBRARY_PATH=${GOLAEM_INSTALL_PATH}/lib:\&
# Set Environment Variables for Houdini
export HOUDINI_DSO_PATH=${GOLAEM_INSTALL_PATH}/procedurals/houdini:\&
export PYTHONPATH=${GOLAEM_INSTALL_PATH}/procedurals/houdini/python:\&
export HOUDINI_TOOLBAR_PATH=${GOLAEM_INSTALL_PATH}/procedurals/houdini/shelf:\&
export HOUDINI_UI_ICON_PATH=${GOLAEM_INSTALL_PATH}/procedurals/houdini/icons:\&
#export HOUDINI_DSO_ERROR=3
# Launch Houdini

/opt/hfs17.5.327/bin/houdinifx

Windows

:: Set Environment Variables for Golaem
set GOLAEM_INSTALL_PATH=C:\Golaem\Golaem-7.1-Houdini17.5
set PATH=C:\Golaem\Golaem-7.1-Houdini17.5\bin;^&
:: Set Environment Variables for Houdini
set HOUDINI_DSO_PATH=%GOLAEM_INSTALL_PATH%\procedurals\houdini;^&
set PYTHONPATH=%GOLAEM_INSTALL_PATH%\procedurals\houdini\python;^&
set HOUDINI_TOOLBAR_PATH=%GOLAEM_INSTALL_PATH%\procedurals\houdini\shelf;^&
set HOUDINI_UI_ICON_PATH=%GOLAEM_INSTALL_PATH%\procedurals\houdini\icons;^&
set HOUDINI_DSO_ERROR=3
:: Launch Houdini
"C:\Program Files\Side Effects Software\Houdini 17.5\houdinifx.exe"

Troubleshoot

You can also uncomment the line setting the HOUDINI_DSO_ERROR environment variable to 3 in order to get more logs and check what is the issue when loading the plugin within Houdini

Licensing the Golaem For Houdini Plugin

In order to run without rendering watermarks (actually parts of meshes removed), a Golaem For Houdini license is mandatory. It need to be installed the same way than the Golaem For Maya licenses. Please check http://license.mayacrowd.com/#houdini. It is also possible to use the same Environment Variables to avoid fetching of licenses or PLE Licenses

Once installed, you can check the status of your license by looking at the Houdini log, the pop up message displayed when the plugin is loaded or in the Golaem Shelf / About Menu:

If you run the Golaem for Houdini plugin without a license, it will be in PLE mode. Therefore some meshes will be missing on your characters. This is done on purpose, of course with a license, all meshes will be there.

Replaying / Rendering a Simulation

Setting Shading Variation

Editing the Simulation

Simulation results (character positions, orientations, postures) must be edited using the Simulation Layout Tool in Houdini or Maya. You can see the results of these edits by changing the current frame in Houdini.

If you'd like to change any Crowd Shader properties (texture, color, displacement, multi matte IDs...), it can be done on the assigned Materials in Houdini (see above).

If you'd like to change the assets repartition or the shading assignment, it must be done in the Character Maker in Maya. When done, you just need to save the changes in the Character File. Reexporting the library file is not required.