Houdini 18.0 Rendering

Rendering with AIR

To...Do this

Set up the default rendering controls

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


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 up "View: RenderMan"

Set the environment variable HOUDINI_VIEW_RMAN. For 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.

Override the shader path

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 customize the path, you should include $HFS/ri_shaders in the path for light shaders. If the shader path is left untouched, then Houdini will look for directories named ri_shaders in the HOUDINI_PATH.

Customize object parameters

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
See also


Mantra user guide



Next steps


Other renderers