Valve has released the mechanical CAD geometry for the Steam Controller under a Creative Commons license.
This means that community members are now able to create custom accessories for the controller. Under Valve's terms, community members are free to share their designs and to 3D print them for free, but they have to get in touch with Valve if they want to sell their creations.
To kick things off, Valve also released a couple of alternate designs for the battery door that include a holster for the USB wireless receiver.
The CAD files for the Steam Controller and the two battery door alternate designs can be found on Steam. The archive contains several eDrawings viewer files: from Creo Express and native Modeling, to neutral exchange and 3D print files – for compatibility with a wide variety of design tools.
VIA: Steam