Second Life University: Episode 22 – PBR Materials

A woman in a white long-sleeved blouse and black miniskirt ponders the heart shaped entwined trees in the center of one of the shopping courts.

With Runitai and Kyle Linden

I’m pausing during my Valentines Day holiday shopping to scribble down a few notes on the recent livestream from SLU. I think this is more of a Lab Gab than an SLU episode, but nobody asked me anyway. And what maters is the exceedingly wonderous stuff that this live stream shows is coming!

Strawberry Linden, Runitai Linden (DaveP), and Kyle Linden stand in a test room in front of several ranks of test characters. Reflections of all three can be seen on the floor.

PBR (or Physically Based Rendering) is a different way of presenting computer graphic materials with the goal of more realistically modeling the flow of light, allowing generation of more photorealistic results. In this episode, Runitai and Kyle walk Strawberry through some of the details of how this rendering technique will be brought into Second Life.

Note! None of this stuff is out on the production grid right now. All the action in this video happens in a special “rumpus room” region in the beta grid. So, it will be some time yet before this is virtual reality for the rest of us. (That said, they are strongly encouraging content creators to get copied to the beta grid so they can experiment with their stuff and make sure it doesn’t break.)

I won’t do an exhaustive dissection of the whole video here. Everybody, particularly content creators, should watch the whole thing themselves. But a few high points.

Right off the bat, notice that there are full avatar reflections on the floor of the studio where they start out. More about how this was done later.

The Big Question

First, what everybody really wants to know: will I need a 4080? Jumping ahead to 30:13, Strawberry relays the question will we need a really great video card in order to see all this cool stuff? DaveP sez no. It will require OpenGL 4 (most by far already have it). However, because of other associated optimizations, frame rates are likely to actually go up. [Yay!]

Materials as Objects

At 12:00, Strawberry askes to be walked through making something shiny. The thing I noticed right away is that materials are now objects in inventory. You can just drag them onto a face to apply them. This is sort of like how they made environment settings full Second Life objects. Presumably, we will be able to trade and sell materials.

Reflection Probes

At about 19:10 discussion of reflection probes gets going. This sounds like it will be an involved topic. Setting up a scene to work properly is going to require the placement of reflection probes. Their placement is something of an art. “They’re expensive. You only get 256 of them at a time.” [I think I can live with that. But it looks like I have some reading to do.]

There are box reflection probes that offer a nice shortcut for defining what a room is to the rendering algorithm.

In the coming world, things like houses and such should include reflection probes in the build. The general users shouldn’t need to know a thing about them.

Door Knobs/Plates!

Starting at 25:06 DaveP and Strawberry turn their attention to a pair of door knobs/plates and use them to illustrate how the new materials will make things look way better. See the image below for a spoiler.

A pair of door knobs and plates illustrate the effects of brass and chrome PBR materials. The chrome door plate shows exterior reflections.

The Hat

One thing that got my attention all through the video was DaveP’s hat. It looks like a flexy with negative gravity and a lot of tension; wobbles like gelatin and is mirror reflective. For some reason, I had it in my head that we didn’t do materials with felxies. (In fairness, I very rarely work with them.) A quick experiment shows otherwise. Once again, I learn something every time I watch one of these videos.


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