Brian Karis

hearing AI company CEOs excitedly telling you how "we can now all finally become managers" without blinking makes me want to pack my bags and move to the moon

I've been working with Spherical Gaussians recently as a representation for irradiance in realtime raytracing.

Ended up deriving quite a few new approximations relating to SGs and diffuse lighting. Ended up with something both cheap and accurate. Check it out:

www.shadertoy.com/view/WX3fRB

I could skip all the copious amount of visual aids slides demand as well as the hours of practicing speaking it. In the end I’m not sure this turned out better in either way, just different. I’m curious to hear your feedback.

After doing numerous talks I decided a written medium the viewer could work through in their own time could better convey the low level details I tend to want to get into. I also imagined it would be less work following “I didn't have time to write a short letter, so I wrote a long one instead.”

Nanite Tessellation Nanite Tessellation, aka Nanite Dynamic Tessellation, aka Nanite Dynamic Displacement was the next major feature I worked on after Nanite it...

I'm finally writing up how Nanite Tessellation works. The first few blogs posts are up. More will be coming.
graphicrants.blogspot.com/2026/02/nani...

YouTube video by Wookash Podcast Game Architectures with Alex Evans and Anton Mikhailov

i had a chat with lukasz and @antovsky about gamedev and stuff, if youre into that sort of thing! the middle hour is the juiciest but its all fantastic, ofc ;) youtu.be/mFBmoCv5EcQ?...

@leepetty.bsky.social @p1xelcoder.bsky.social @ianmcque.bsky.social Keeper is an artistic and technical masterpiece! Bravo! Utterly unique in every way. Gobsmacked.

Never would I have guessed that a Doublefine game would rise to the top of my list as a showcase of #ue5 tech.

YouTube video by Aaron Hertzmann Can Computers Create Art? Lessons from art history

Here's a recording of my talk on the role of computers in making art, including so-called "AI", which was presented as the opening keynote of SIGGRAPH 2025, incorporating lessons from the history of computer graphics, photography, modern art, and philosophy of art. www.youtube.com/watch?v=c2YR... 1/

New blog post: Outlining an alternative path to learn graphics programming.

themaister.net/blog/2025/10...

New blog post! In "Billions of triangles in minutes" we'll walk through hierarchical cluster level of detail generation of, well, billions of triangles in minutes. Reposts welcome!

zeux.io/2025/09/30/b...

The new Nanite Foliage Voxel representation is an absolute game changer for distant environments, density preservation is pretty much perfect.
5 min test scene i whipped up here.
~1 million 20 million poly trees scattered with PCG
#UE5 #UnrealEngine #GameDev #EnvironmentArt #RealTime

My talk is out! c0de517e.com/023_hpg.htm

All HPG 2025 papers are now available on the EG digital library.
CGF papers: diglib.eg.org/handle/10.23...
Conference papers: diglib.eg.org/handle/10.23...
It has been a huge honor to act as HPG papers chair and guest editor and I look forward to an exciting program in Copenhagen.

I signed and encourage colleagues to do the same.

Venue selection is fraught. Inevitably attendees will encounter visa issues, distance, expense, local politics, and other challenges. This venue, however, is simply unsafe for LGBTQ+ researchers, and the leadership's defensiveness is unacceptable.

This is a great thread @hillsguy.bsky.social, I'll add a bit more context here for anyone interested.

Yes there's no fancy sim - it just uses a water interaction buffer as a target for the particle system rendering, so we could use the power of particle system we already have.

The SIGGRAPH Physically Based Shading course is back this year: blog.selfshadow.com/publications...

Yes but not ready to share anything yet

Thanks Sean!

Includes this great video showing how the Nanite Foliage seamlessly LODs. No popping. No harsh transitions. Good appearance preservation (although this light direction is overly generous).

YouTube video by Unreal Engine Livestream 2, Day 2 | Unreal Fest 2025

More rendering tech details on how the Witcher 4 UE5 demo works youtu.be/0X6amtHcrUE?...

1 minor detail, it can switch to voxels within the twigs themselves as they get further as well. A Nanite cluster can now be either 128 triangles or 128 voxel bricks. That visualization only showed 5 steps but there are as many as it takes to halve the count until there is 1 root cluster.

Great video from DF!

Really good explanation from @dachsjaeger.bsky.social about how foliage has been done in the past, the problems with them, and why this new approach was needed.

I’ve wondered the same. We haven’t yet explored any alternative uses for these new tools yet. It probably can’t beat the best hand modeled hair cards but it seems like it could be great as an auto generated LOD for spline based grooms.

Yes. This has been one of the most challenging parts of the problem. If opacity per voxel is too expensive, voxels can either be 100% covered or not, which do I fill? And determine that relatively fast since the Nanite build for a mesh needs to take <1min.

A cluster in Nanite typically is up to 128 triangles. Voxel clusters are 128 4x4x4 bricks. Brick positions are fixed point so no precision problems.

Really though gaps aren’t a key concern for voxels since they are used primarily for subpixel features which result in partial coverage.

Correct. 3 separate features: assemblies, skeletal meshes, and voxels. None of which is strictly foliage. Each can be used without the other. Can make assemblies and keep as meshes, like the repeated elements on this shield from the original UE5 demo. Or voxelize a single Nanite mesh.

Sure. We didn't get time to do the wind animation as an actual physics sim but want to in the future. AC Shadows wind looks amazing and we aren't there yet.

Breaking off branches could be a problem since Nanite assembly HLOD needs to merge things. They aren't individual branches in the distance.

Agreed

5.7 for first version and then probably more significant improvements for 5.8.

YouTube video by Unreal Engine The Witcher 4 Unreal Engine 5 Tech Demo 4K | State of Unreal | Unreal Fest Orlando

The new Witcher 4 UE5.6 tech demo that was shown today is the most amazing realtime tech demo I've seen yet. Nanite Foliage is particularly impressive- I've always liked the idea of voxel-based LOD and this is the best implementation I've ever seen!

www.youtube.com/watch?v=aorR...