Scene Description

Our scene shows a rocky mound with swords embedded in the stone beneath an eerie, otherworldly red sky. At its peak stands an intertwined angel-and-devil statue, contrasting the environment with a blue iridescent sheen.
As the viewer inspects the image, they are invited to wonder what happened here: the aftermath of a battle, or the end of a long conflict, crowned by a looming dichotomy—an abstract take on war and what remains afterward.
One might also take note of the placement of the swords.
Our final render took … on an AMD Ryzen 7 1700.
Here are some intermediate results and renders:

Inspiration reference

Our inspiration

Early summit model

First model of our summit

First render of the scene

Our first render of the scene

Iridescence test render

Testing iridescence

Early version of the scene with iridescent statue

Initial scene using our iridescent statue model

Environment iteration to showcase iridescence

We changed the environment to make the iridescent statue stand out more

Final look development render

This led to the final look of our scene

Area Lights

We sample a random point on the light geometry and evaluate radiance proportional to its area using a solid-angle PDF.
Challenge: adding the cosTheta term correctly in our path tracer for area lights.

Area light result Point light result
Point Light
Area Light

Improved Environment Sampling

We bias the selection of the sampled areas of the envmap towards areas with more luminance, which then contribute more to the scene.
Challenges: double sampling, as well as “exploding” environment maps.

With importance sampling Uniform environment sampling
Uniform Sampling
Importance Sampling

Normal Mapping

We add fine detail to simple meshes using a normal map that perturbs the shading normal.
Challenge: inverted normals were hard to detect.

With normal mapping Without normal mapping
Without Normal Mapping
With Normal Mapping

Iridescence

We approximate an iridescent effect using thin-film interference and Airy summation to model scattering, polarization, and phase changes for dielectric films on top of conductors.
Challenges: manually adding iridescence (not supported by Blender or our exporter) and getting the math/physics right.

Iridescence feature showcase

Thin Lens

We achieve depth of field by sampling rays through a lens and focusing them at a chosen focal distance, which blurs objects away from the focal plane.
Challenges: …

With thin lens depth of field Without thin lens depth of field
Without Thin Lens
With Thin Lens

Alpha Masking

Hits are rejected using the texture alpha value and an RNG test.
Challenge: creating a test scene that exports as a valid XML file.

Alpha masking feature showcase

Image Denoising

Using Intel Open Image Denoise (OIDN), we can produce near noise-free results even at low sample counts.
Challenges: ensuring compatibility on both Windows and Linux.

Denoised image using OIDN Noisy image without denoising
Without OIDN
With OIDN

Credits

Lastly, here are the credits for third-party assets used.

Angel and devil statue

by KRONOS77

Red sky HDR

by Youssef Ismail

Swords

by Ellen-

Rock texture

by Dimitrios Savva