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5
Reality Converter & PBR Materials Written by Chris Language

In the previous chapter, you learned how to convert virtual content into a usable USDZ file format with USD Python Tools. However, the conversion process is tedious and not user-friendly.

In early 2020, Apple introduced a new app specifically designed to make USDZ conversion as simple and user-friendly as possible: Reality Converter.

What is Reality Converter?

Reality Converter is a macOS-based app that makes it easy to convert, view and customize USDZ content. It offers a simple drag and drop interface with support for common 3D file formats like .obj, .gltf and .usd.

It allows you to customize material properties with your own textures and edit the USDZ metadata. With its WYSIWYG (What You See Is What You Get) design, you can easily preview your virtual content under various lighting conditions. Once you’re happy with the end result, it’s simple to export your model as a USDZ file.

Note: At the time of writing, Reality Converter is still in Beta and access to it requires an Apple Developer account. Future versions might install along with Xcode, just as Reality Composer does.

Adding a 3D model

Download Reality Converter from this link: https://apple.co/38LbwqM. Then install and start it.

PBR materials

Reality Composer and the USDZ file format use the PBR lighting model, which offers diffuse lighting with a realistic abstraction of physical lights and materials.

Base Color map

The Base Color, or Diffuse, map gives the geometry a base color texture. Typically, this texture defines what the object is regardless of any lights and special effects.

Normal map

The Normal map is a special kind of map that controls how light reflects off the surface. Technically, it defines how the surface combines with detailed surface normal data that bends reflected light off the surface. It ultimately makes the surface appear to have more detail in its geometry without needing a higher poly count.

Occlusion map

The Occlusion, or Ambient Occlusion, map defines the amount of ambient light that reaches certain parts of the geometry. When looking at real-world objects, you’ll notice that light typically struggles to reach tight spaces, like the lines of stitching between the ball’s patches.

Metallic map

One of the key trademarks of PBR materials is the use of Metallic maps that define how metallic or dielectric — that is, non-metallic or plastic — a surface is.

Roughness map

PBR materials use Roughness maps to define how smooth or rough a surface is. They approximate the microscopic detail of real-world surfaces to produce a shiny or matte appearance.

Emissive map

The Emissive map overrides all lighting and shading information to create a light-emitting effect.

Clearcoat map

The Clearcoat map simulates a thin reflective layer on top of a surface, like the transparent coating of a car’s paint job. It can also represent varnish, water or anything else that benefits from multiple layers.

Clearcoat Roughness map

The Clearcoat Roughness map works in conjunction with the Clearcoat map, defining how smooth or rough the clearcoat on top of the surface is.

Opacity map

The Opacity map makes certain parts of the geometric surface appear either opaque or transparent.

Environment

Reality Converter has another cool feature that allows you to preview your virtual content under various lighting conditions.

Exposure

Exposure controls the amount of light to which the virtual content is exposed. Reality Converter allows you to test that, too.

Properties

Your model is almost done, but there’s one step left to do: You need to set the metadata for your virtual content before you share it with the world.

Sharing

You’ve finished your model. It’s time to test it on your iPhone or iPad.

Exporting USDZ

Now that you’ve added all of the textures and tested your 3D model under various lighting and real-life conditions, it’s time to export the USDZ file.

Key points

You’ve reached the end of the chapter and you now know how to convert your content using Reality Converter.

6. Image Anchors 4. USDZ Files & USD Python Tools

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