AMD engineers have submitted a HIP-RT update for Blender developers ahead of the big Blender 5.0 release to enhance the RDNA4 ray-tracing performance.
Last week a pull request was submitted for Blender’s Cycles engine to update the HIP-RT code. In particular, pulling in the recently-released HIP RT 3.0 code that brings new RDNA4 ray-tracing features. New RDNA 4 support includes compressed BVH8 and triangle packets, intersectable instances, and oriented bounding boxes. There are also other improvements too.
With the updated HIP-RT code for Blender 5.0 there are the new Navi 4 (RDNA4) features though it does up the requirements to using HIP SDK 6.4+ on Windows or ROCm 7.0+ on Linux. If running an older version of the ROCm/HIP code, HIP-RT will fallback to the old codepath that is said to now pose a 15~20% performance loss.
“HIP-RT 3
– Enables support for Navi4 RT features. Navi4 features require HIP SDK 6.4+ on Windows, ROCm 7+ on Linux. In the absence of the appropriate compiler, HIP-RT falls back to pre-RDNA4 code path (~15-20% performance loss)
– Compresses embedded kernel in hiprt library (~10x reduction in size)
– Fixes handling of embedded Balanced BVH kernel”
Some nice improvements with the HIP-RT update for Blender. Blender 5.0 is currently in its alpha stage until the start of October. So with the better part of one month to still land features, this new HIP-RT code should safely make it in time for Blender 5.0. The Blender 5.0 beta period that focuses on bug-fixes will begin in October, a Blender 5.0 release candidate is expected around 5 November, and the Blender 5.0 stable release hopefully will take place on 11 November.
Per this week’s Blender render and cycles meeting, beyond the HIP-RT update being under review they are also working on updating the Intel libraries for the Intel oneAPI ray-tracing support. Though they mention with the updated Intel libraries only Ubuntu 24.04 LTS and newer will be supported with losing out on oneAPI GPU rendering for older Linux releases.
