From the course: Learning Marmoset Toolbag

What is PBR? - Marmoset Tutorial

From the course: Learning Marmoset Toolbag

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What is PBR?

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- [Instructor] Toolbag uses a system called PBR to light the model and deal with the materials that are applied to the model. Now you might be wondering what PBR is. Well, to start with, PBR is an acronym for Physically Based Rendering, which is a pretty neat development for game and 3D artists. No longer does the 3D artist need to spend hours creating texture maps in photoshop; now programs like Quixel or Substance can generate maps that are created using realistic shading and lighting models along with measured surface values, to accurately represent real world materials. Now to point out the differences between PBR and our older systems of applying maps, I've opened up this model of my cannon. Over here in this big window we can see the background image that is being used to light the cannon. That background image isn't showing right now, but I can turn it on by going under backdrop and turning on sky. Now it's hard to see the model with the background turned on, but we'll use it as a example. If I move that sky background around, you can see that it changes the lighting on the model. It's hard to see, again, with the background on, so I'm going to turn it off and then move it. Now it still will move around, and you can see that lighting change. One way to think of this system is as a dome sitting over the model where the image of the background is on the dome with LED lights at each pixel, shining down on your model. So if I rotate the dome, well the lighting on the model rotates around it. You can also think of this as the real world equivalent, where a rainy day or a sunny day are going to effect the same object differently. Marmoset can recreate these surfaces, so that the artist can see what their model, with maps applied, will look like in specific game engines. The map types you might be familiar with change a bit as well. Where older texture pipelines call for diffuse and specular maps, you'll find that most PBR pipelines use albedo, and gloss maps. Metalness, ambient occlusion, roughness, and microsurface maps are just a few of the map types that you can expect to deal with when dealing in a PBR based system. The names of the maps change depending on the game engine you're using, so while these are the names that Toolbag uses, your game engine might use slightly different names. The basic things you need to know about PBR are that there are two main workflows, one for metal, and one for non metal surfaces. Generally, gloss, roughness or microsurface settings control reflectivity, and that multiple maps including normal, albedo, gloss, ambient occlusion and detail maps are used to achieve realistic surface properties that can be displayed in many current game engines. Toolbag is simply a rendering tool. The maps necessary to achieve the surfaces displayed need to be generated in programs such as Quixel or Substance Painter. We'll look at how Toolbag deals with various maps and settings in the next few videos.

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