usd.graphics

USD for all, all for USD.

A guide to understanding and building 3D worlds.

INTRODUCTION

This page introduces everyone to the world of 3D.

From the theory to the practice of creating 3d-content, using OpenUSD as the tool for making 3d-content.

3D Worlds

From Videogames to Movies, going through Fashion, Museums, Architecture and more, the use of “3D” is everywhere.

Being everywhere, one would think that a 3D-world is well-defined by standards, about how to create 3d-content, how to visualize it or render it, or how to interact with it.

It is unfortunately not like that (yet).

A videogame, a movie, a website for buying shoes, a virtual-visit to a museum, a 3d-preview of your new bathroom, your avatar on your favourite videogame console; they all use their own “standards”, they all have their authoring or rendering tools, usually only valid in their own contexts.

I might have been a bit too extreme here, but overall, this is where we are.

There is an effort across various experts of the 3d-industry (allow me the generic industry term here) to create standards, to use naming conventions, to make sure that in the same way I can buy an real t-shirt in a shop, and wear it at home or at a basketball match or for walking on the streets, then I should be able to do the same with 3d-content.

As well as there are rules and standards in the real-world, so there should be in the 3d-world.

We are not at a point where we can do this in the 3d-world (yet, again).

There are actually multiple “3d-world” with various rules and standards.

And various vendors (those making tools for creating 3d-content) have decided to support multiple 3d-worlds, with their rules and standards, to make it easier for a content-creator to possibly use one tool to create a “t-shirt” once and then “export it” or “save it” for multiple “3d-worlds”.

The Metaverse could, in the future, be a “3d-world”, with rules and standards. Multiple-metaverses, if they will exist, will need to be able to communicate with each other, if they have different rules and standards.

Various 3d-formats (OBJ,FBX,PLY,3DS,glTF,etc) are the “fabric of the t-shirt in its own 3d-world with rules and standards”.

USD ( Universal Scene Description ) is trying to become the “universal” 3d-format, replacing or hiding, behind a unified interface, the aforementioned formats.

3D Guidelines

Important

Terms present in this document are to be used as guidelines. There aren’t defined standards yet!

To understand a 3d-world, we need to understand the real-world first, and identify its components.

When identifying objects in the real-world, we also have to understand the level of granularity we want to use.

If I ask you to count all objects in a room, you are not going to tell me how many electrons or molecules are in that room. We have an agreed assumption that a chair is an object, because you can consider it as a whole ensemble of multiple smaller components.

If you count 3 chairs in your room, and those chairs are all the same brand, we can say that there is a brand-X chair, repeated 3 times in your room.

In the 3d-world, we usually refer to the 3 chairs as elements and the brand-X chair is usually as an asset.

In this particular context, since the 3 elements are all from the same asset, they could be referenced to as instances of the chair.

The room, being the environment in which the chairs are, is the layout ( often called environment interchangeably ).

In a similar way, we can look at a forest with its trees:

The forest is the layout. There is then a form of a pine-tree, which we can call a pine tree asset, which is repeated multiple times to make all the pine-trees, the elements of the layout.

In general it is very important, in the 3d-world, that each element has a unique name ( also called identifier ).

Production pipelines

Coming soon…

MUST READS

There are plenty of resources online about OpenUSD. The followings are some must-reads to start with and they are those that you want to bookmark as you will get back to them quite often.

ENVIRONMENT SETUP

Coming soon…

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