UbiBlog has word on the release of a new high resolution texture pack for Rainbow Six Siege as free DLC through Uplay or Steam. Here's word:

If you’re playing Rainbow Six Siege on PC, there’s an extra treat waiting for you today alongside the latest update – and it’s one you’ll definitely want to grab if you’re playing on a higher-end rig. Download the Ultra HD Texture Pack, and you’ll get new weapon and character textures that look amazing at resolutions up to 4K.

You don’t need a 4K monitor or ultra-high-end graphics card to take advantage of the new textures, however. For example, if you’re running a GPU with at least 4 GB of memory, you’ll notice a difference when using the new textures between 1080p and 1440p resolutions. Rainbow Six Siege looks even better on a GPU with 6 GB or more, which lets players take full advantage of the Ultra HD Texture Pack at 4K resolution.

Finally, those running dual GPUs with 6 GB or more each will be able to breach walls and rescue hostages with the game looking its absolute sharpest, with 4K resolution, Ultra HD textures and the highest settings for lighting and shading.