I noticed that their coding style consistently uses the spelled-out Boolean operator keywords "not", "and", "or". Can't think of any other C++ codebases that use this -- can anyone else?
Pixar Universal Scene Description
31–36 of 36 posts
Re: Pixar Universal Scene Description
#32Earlier quoted context omitted.
Alembic is a baking format. Slightly different use cases. Usd has support for Alembic baked nodes: https://github.com/PixarAnimationStudios/USD/tree/2eb01f5cd4...
Could you explain what "baking" means in computer graphics? I spent a few minutes googling, and all I've learned so far is that: - there isn't "baking", there's "texture baking", "light baking", and many other " baking" - it seems to mean any kind of precomputing stuff - apparently the term was coined by Pixar in some paper
> - it seems to mean any kind of precomputing stuff
Yes, it's a fancy word for that.
But when hearing that word (rather than 'precompute' or 'compile') it implies a few things.
Usually it means precomputing to a file rather than memory.
Mostly, but not always, baking implies generating a large amount of data from a smaller amount.
Typically the source description is for a whole sequence or animation, but the baked data will be a distinct set of data for each frame.
Re: Pixar Universal Scene Description
#33Earlier quoted context omitted.
> precomputing stuff Correct. In this context it means turning the geometry into frame by frame mesh data so that your animation isn't dependent on anything like bones, cloth simulation, muscle/skin simulation, soft or rigid body dynamics, inverse kinematics in the rig, expressions on the bones of the rig etc. Not only does it break dependencies, but it is also easier to get that geometry into another part of the pip…
So does a renderer such as RenderMan use a baked format like Alembic or a format like USD?
The basic answer is it uses neither file format but what it does use has similar attributes to both.
RenderMan uses RIB files for its scene description and RIB files contain geometry. This means that one RIB file would typically contain a frame of data and source the shaders and textures from separate file paths.
Re: Pixar Universal Scene Description
#34There was a demo of some USD-related software at SIGGRAPH, for context: https://www.youtube.com/watch?v=JmH4KYcmHOo
Hey! That's our company's flagship laptop in the wild! https://system76.com/laptops/bonobo
A bit OT and I hate to be a pest... but can you guys please start offering laptops with more than 1080p displays? It's almost Kafka-esque that my phone has 77% more pixels than a $2,500 graphics workstation laptop.
Re: Pixar Universal Scene Description
#35Currently reading The Pixar Touch by David A. Price and they talk a lot about the types of software and standards for rendering they had to create over the years. Incredibly interesting looking back at what they were able to achieve. A talented crew for sure. For those interested: https://www.goodreads.com/book/show/2632830-the-pixar-touch
I just finished Creativity, Inc. and it was a pretty good look at how Pixar evolved. Also highly recommended.
Re: Pixar Universal Scene Description
#36Earlier quoted context omitted.
Alembic is a baking format. Slightly different use cases. Usd has support for Alembic baked nodes: https://github.com/PixarAnimationStudios/USD/tree/2eb01f5cd4...
Could you explain what "baking" means in computer graphics? I spent a few minutes googling, and all I've learned so far is that: - there isn't "baking", there's "texture baking", "light baking", and many other " baking" - it seems to mean any kind of precomputing stuff - apparently the term was coined by Pixar in some paper
> Could you explain what "baking" means in computer graphics?
It means that the code/configuration used to produce a particular result (e.g. an animation sequence) isn't accessible anymore, but the result is.
For example, Houdini (http://www.sidefx.com) lets you procedurally animate 3D geometry, using a collection of nodes, scripts, etc. This is very useful for authoring, but is extremely heavy when all you want to do is render the resulting animation.
So, you "bake" the animation to a file (Alembic is a popular option today, which Houdini supports) and then you use the baked file during your rendering. None of the code and computation that produced the animation need to be available to the renderer.
Put another way: "baking" is the CG term for "memoizing" the result of a computational process.