The Hair Interface available since 3ds Max 7.5 provides some useful utility functions related to the Hair Extension.

Interface:Hair 

Methods:

<void>Purge()   

Removes all traces of Hair elements from the current scene, including all HairMod WSMs from all "hairy" objects and the HairEffect RenderEffect from the Render Effects list in the Effects tab of the Environment and Effects dialog.

<void> AddMod <node array> nodes 

Adds a HairMod to all supplied nodes. Shows the Presets dialog to pick a hair stile first.

<void> AddEffect <boolean> showGUI 

Adds a HairEffect RenderEffect to the Effects dialog. If the showGUI argument is passed as true, also opens the Environment and Effects dialog to show the Hair Render user interface.

If a Hair Render effect already exists on the list of Effects and true is passed as argument, only opens the dialog with the User Interface.

<boolean> CanUseLights <node array> nodes 

Returns true if at least one of the supplied lights can be used, false if none of the supplied light can be used by the hair renderer.

<void> AddHairProperties <node array> nodes 

Adds a "Hair Light Attr" rollout to one or more spot lights passed as argument.If any of the nodes are not spot lights, they will be ignored. Corresponds to the "Add hair properties" button in the Lighting group of controls in the Hair & Fur Effect's rollout.

<void> RemoveHairProperties <node array> nodes 

Removes the "Hair Light Attr" rollout from one or more spot lights passed as argument. If any of the nodes are not spot lights, they will be ignored. Corresponds to the "Remove hair properties" button in the Lighting group of controls in the Hair & Fur Effect's rollout.

<void>ExportDRA <filename> draFileName <time> time <integer> voxels 

Exports a DRA file to the specified file name at the given time using the supplied voxel count.

<void> ExportDRA2 <filename> draFileName <time> time <integer> voxels <&integer array> shaveNodeIDs 

Exports a DRA file to the specified file name at the given time using the supplied voxel count and array of integer node IDs.

Available in 3ds Max 2010 and higher.