Tuesday, February 6th, 2024 Posted by Jim Thacker

See Disney’s Moana island data set ray traced on a single AMD GPU

AMD has posted an image of Walt Disney Animation Studios’ Moana island scene rendered on a single AMD GPU as a promo for HIP RT 2.2, the latest version of its ray tracing library.

The multi-billion primitive scene was rendered on an AMD Radeon Pro W7900 GPU using a fork of open-source renderer pbrt ported to run on AMD GPUs using the firm’s HIP API and HIP RT, taking advantage of the support for multi-level instancing introduced in HIP RT 2.2.

A classic large production data set for testing renderers
First released publicly in 2018, and updated to USD in 2022, the Moana Island Scene is a classic data set for artists and researchers looking to stress-test renderers.

A version of the production scene for Motunui island from 2016 animated feature Moana, the data set runs to tens of billions of primitives when fully instantiated.

(The documentation for the original scene says 15 billion, while AMD’s blog post says its version ran to 31 billion, but it’s certainly Very Large.)

Rendered using a fork of pbrt ported to run on AMD GPUs
Although Walt Disney Animation Studios provides versions of the scene configured for two publicly available renderers – RenderMan and open-source ray tracing renderer pbrt – by default, both support GPU rendering on NVIDIA GPUs only.

To generate its demo render, AMD created a fork of pbrt V4, the latest version of pbrt’s source code, porting the GPU backend to run on its graphics cards using HIP, its runtime API and kernel language, and HIP RT, its ray tracing library.

HIP has previously been used to create AMD-compatible versions of Redshift and Blender’s Cycles renderer, which also has an experimental HIP RT option for GPU ray tracing.

Benefits from support for multi-level instancing in HIP RT 2.2
At 30GB unpacked, the pbrt v4 version of the Moana Island Scene is small enough to fit into GPU memory on AMD’s 48GB Radeon Pro W7900 card, but benefits from multi-level instancing, introduced in HIP RT 2.2, the latest version of the library.

In the case of a scene like Motunui island, multi-level instancing makes it possible to instantiate leaves on a tree, then instantiate the tree itself as part of a forest.

AMD says that this “may reduce memory requirements significantly” and is “one of the important features that allows the rendering on a GPU with limited VRAM”.

License and system requirements
The source code for HIP is available under a MIT license. The HIP RT library is a free download governed by AMD’s HIP RT license.

Read more about HIP RT 2.2 on AMD’s blog

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