Set the environment variable HOUDINI_DEFAULT_RIB_RENDERER. The value of this variable should be one of the supported RIB renderers.

For AIR, you would choose

export HOUDINI_DEFAULT_RIB_RENDERER=air4.0

or whatever the current version being used is.

When this variable is set, VOPs will compile using shaded (the AIR shader compiler, and the RenderMan output driver will have settings which apply for AIR.

Set the environment variable HOUDINI_VIEW_RMAN. For AIR:

export HOUDINI_VIEW_RMAN=air

This variable determines the command to run when View: RenderMan is chosen from the viewport. This variable is also used for the shader ball.

By default, Houdini will set the path to the default path that the render expects. If you want, you can override the shader path in two ways.

1. Set the path by adding the rendering parameter to the output driver (preferred method).

2. Set the environment variable HOUDINI_RI_SHADERPATH.

If you are using AIR as a primary renderer, you may not want to see all of the mantra parameters in your geometry objects. You can customize Houdini so that instead, you’ll see the parameters which are appropriate for AIR.

The mantra parameters are created in the creation script for the geometry object. This script can be found in $HH/scripts/obj/geo.cmd. The line which adds the rendering properties is

To change the default parameters, do the following:

1. Decide which properties you want for the renderer. For example: ri_rendersubd, ri_renderpoints, ri_computeN, ri_curvebasis, and ri_motionfactor.

2. Copy the file $HH/scripts/obj/geo.cmd to a location earlier in the HOUDINI_PATH (i.e. /houdini9.0/scripts/obj/geo.cmd).

3. Edit the script replacing the opproperty command with

   opproperty -f -F Render $arg1 air4.0 ri_rendersubd
   opproperty -f -F Render $arg1 air4.0 ri_renderpoints
   opproperty -f -F Render $arg1 air4.0 ri_computeN
   opproperty -f -F Render $arg1 air4.0 ri_curvebasis
   opproperty -f -F Render $arg1 air4.0 ri_motionfactor
   etc.