Challenge 08: Sliced Bread. First challenge on the revamped platform. I'm super intrigued how you all will approach this. It's one of these open-ended shading quests that I personally have never seen executed to a believable degree. Volumes? Geometry? Curves? Any route to the correct end result is allowed.
This months challenge (and the challenges onwards) will be judged by the moderator team. We're a bunch of unbiased shading nerds working at various high-end animation/vfx studios. The deadline for the challenge is 1st of March 2019, 00:00 PCT
Reference imagery

A high-res .tif version of this image is included in the package.
Getting started
The initial scene setup is very straightforward and only takes 5 minutes. It is important that we standardise scene conditions between contributors, so please make sure that you're not setting up the scene differently.
- Download and extract the .zip package (this was updated 5th of Feb 2019).
- Open or load in the alembic, containing the scene geometry and camera.
- Assign a lambertian material to the floor geometry, assign the checker texture map [tex/checker_floor.tif] to the color slot.
- Repeat step 3 for the macbeth chart [tex/macbeth_chart.tif].
- Create an HDRI light and rotate it in these axis: [-14, 56, 0] (xyz respectively)
The default lighting setup should look like the following. (If you DCC's coordinate system is different, just eyeball it. It should be easy enough with a strong directional light like this.)

Please make sure to post renders using this setup. It is allowed to post extra renders using your own light setup. Since the shared light setup is at the core of the challenge, this will be heavily moderated. You've been warned!
What is expected of you?
This month, only one render needs to be submitted. The focus of these challenges is on sharing shading knowledge. Explain the shading setup in as much detail as you can be bothered to do. Think of shaders.xyz as a sort of open source project. Please, also share your scene file if possible. This is not a requirement, but would be very nice. About creating extra geometry - just try to think if it would work in a shading pipeline. If you think it would be practical, go for it. I don't want to limit anyone's amazingly capable brains.
PLEASE NOTE:
Feel free to post WIPs in this thread.
To tag others in a post, use the "@" symbol.
That's all! The winner gets picked by the admin team on the 1st of March, 2019 and will receive an exclusive SHADERS.XYZ t-shirt as well as an invite to become a moderator. Don't forget to motivate others by voting for your favourite submission! Good luck everyone!