Challenge 03: Retroreflector. Time to start brushing up on your light related physics guys. This is not going to be an easy one. It was even incredibly hard to take a good reference picture of this special, yet common material. Not only does it reflect light almost only exactly in the direction of the light hitting the surface, but there are some very cool diffraction effects going on at steep angles too.
This challenge we're going to do some things differently. SHADERSXYZ is actively evolving and we're constantly trying to improve the concept. There's some cool things on the horizon, and this month there will be a voting panel of industry experts in lookdevelopment - working at Pixar, ILM, Framestore, Double NegativeÂ and MPC.
This month, you will also need to submit multiple images (3 total), due to the uniqueness of the material. One where you have a small light source roughly in front of the lens, and two images with the light -20 and 20 degree angles from the camera. This will truly show the retroreflector capacities of your crafted material. If you can, a video of the light source moving around the material will of course show it off the best and get you some respect points, but we can't make that a requirement due to limited computing resources of many participants.
We're also asking to share your scene files from here on, to create more of an open-source spirit, much like what is going on in the Houdini community these days.
It was super interesting to see so many people having a go at our last challenge, exposing the shortfalls of the current light transport algorithms. It seems like especially in the coloured shadow area, there were quite a few issues. Thanks to all who participated. For what it's worth, once again, we've heard some very positive things from top people in the industry. People are watching and it's a fantastic opportunity to show your skillset to them.
In sunlight, just as reference for the microscopic detail.
To fully understand the behavior of the material, video footage is required.
The initial scene setup is very straightforward and only takes 5 minutes. It is important that we standardize scene conditions between contributors, so please make sure that you're not setting up the scene differently.
- Download and extract the .zip package.
- 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 a 3 small light sources (iPhone flashlight in the reference) and place them at the locator positions in the scene file. For each render, only enable one at a time.
The default setup should look like the following. Please ignore the material of the cone.
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, 3 renders need to be submitted. One with the small light source directly in front of the camera and at -20 and 20 degrees. This is necessary to properly judge the shader. 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.
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 June, 2017 and will receive an exclusive SHADERS.XYZ t-shirt (hype!). Don't forget to motivate others by voting for your favorite submission! Good luck everyone!