At their Capsaicin Siggraph event tonight AMD has announced that what was previously announced as the FireRender rendering engine is being officially launched as AMD Radeon ProRender, and this is becoming open-source as part of AMD's GPUOpen initiative.

From AMD's press release:

AMD today announced its powerful physically-based rendering engine is becoming open source, giving developers access to the source code.

As part of GPUOpen, Radeon ProRender (formerly previewed as AMD FireRender) enables creators to bring ideas to life through high-performance applications and workflows enhanced by photorealistic rendering.

GPUOpen is an AMD initiative designed to assist developers in creating ground-breaking games, professional graphics applications and GPU computing applications with much greater performance and lifelike experiences, at no cost and using open development tools and software.

Unlike other renderers, Radeon ProRender can simultaneously use and balance the compute capabilities of multiple GPUs and CPUs – on the same system, at the same time – and deliver state-of-the-art GPU acceleration to produce rapid, accurate results.

Radeon ProRender plugins are available today for many popular 3D content creation applications, including Autodesk® 3ds Max®, SOLIDWORKS by Dassault Systèmes and Rhino®, with Autodesk® Maya® coming soon. Radeon ProRender works across Windows®, OS X and Linux®, and supports AMD GPUs, CPUs and APUs as well as those of other vendors.