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Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

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Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#261

Post by perilunar »

irrational wrote: post #129
gyf304 wrote: post #90

Does anyone remember X3D[1] / VRML? X3D is roughly the same concept, 20-some years ago. Here's a hello world for X3D: https://www.web3d.org/x3d/content/examples/Basic/X3dSpecific... And here's a hello world for OpenUSD: https://www.openusd.org/release/tut_helloworld.html#viewing-... Although X3D is a bit more verbose, a lot of parallels can be drawn between the two, 20 years apart. [1] https://en.wikipedia.org/wiki/X…

I do remember VRML. I read a book about it and spent some time playing around with it in the mid-90s. I didn't follow it closely enough to know when it died off (I'm assuming it died off since I haven't heard it mentioned much in decades).

VRML is still around — it became X3D. It's a different file format but the semantics are much the same.

All the plugins that used to be needed to display VRML online are gone now, but you can still display VRML 2.0/97 files online using JavaScript library called X_ITE [1]. I used it recently to view some old VRML I had saved but could no longer view. Works great.

1. https://create3000.github.io/x_ite/

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#262

Post by perilunar »

can16358p wrote: post #21

So, can we finally say a "JPEG" or "H.264-in-MP4" for 3D content is coming? (I mean as a universally accepted format that just works everywhere, not literally a JPEG on H.264 inside a scene)

Oddly enough, MP4 already includes a 3D content specification: MPEG-4 Part 11:

https://en.wikipedia.org/wiki/MPEG-4_Part_11

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#263

Post by perilunar »

gyf304 wrote: post #90

Does anyone remember X3D[1] / VRML? X3D is roughly the same concept, 20-some years ago. Here's a hello world for X3D: https://www.web3d.org/x3d/content/examples/Basic/X3dSpecific... And here's a hello world for OpenUSD: https://www.openusd.org/release/tut_helloworld.html#viewing-... Although X3D is a bit more verbose, a lot of parallels can be drawn between the two, 20 years apart. [1] https://en.wikipedia.org/wiki/X…

> X3D is roughly the same concept, 20-some years ago

That was my initial thought also.

> Although X3D is a bit more verbose

The USDA file format reminds me a lot of the pre-XML VRML 97 file format, with the curly bracket C-style syntax, #comments, and 'def' everywhere.

https://openusd.org/release/spec_usdpreviewsurface.html#usd-...

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#264

Post by account42 »

doctorpangloss wrote: post #142
MAGZine wrote: post #11

This is a big deal. I used to work at Autodesk, trying to build software that made 3D blueprints available to everyone, everywhere. Rendering things on mobile is hard, in part because you need to writer bespoke renderers, and in part because the data formats for the assets are not aligned. Pixar developed USD, and it should really help to standardize 3D tech. In particular, I hope that USD can help make it easier to…

> Rendering things on mobile is hard I don't know. You can stream Unity to mobile with the service I've authored ( https://appmana.com/watch/theheretic for an example).

> Cooking is hard.

> Just order out bro.

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#265

Post by account42 »

johnnyanmac wrote: post #222
andyferris wrote: post #126

Earlier quoted context omitted.

> human-editable I mean, depends on the human. Most don't know hexadecimal, but know what 3.14 means. The real issue is why do so many float parsers and printers fail to do exact round tripping? Designing a good algorithm for this was a bit difficult, but these days this is a solved problem.

If I had to take a slightly snide guess: because these are low level tools, so there's a 90% chance that these parsers/prints are written in C, or ultimately depend on C implementations. As any C programmer would know, C loves to throw "undefined behavior" at any problem it doesn't bother to document. Which is a lot. That combined with almost zero package management for retrieving things that were solved decades ago…

This is just "hur dur C undefined lol" level of a comment.

If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse. If that means implementations have to ship their own float formatter and parser than so be it - no one is tied to whatever comes with their libc, package manager or no package manager.

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#266

Post by johnnyanmac »

account42 wrote: post #265
johnnyanmac wrote: post #222

Earlier quoted context omitted.

If I had to take a slightly snide guess: because these are low level tools, so there's a 90% chance that these parsers/prints are written in C, or ultimately depend on C implementations. As any C programmer would know, C loves to throw "undefined behavior" at any problem it doesn't bother to document. Which is a lot. That combined with almost zero package management for retrieving things that were solved decades ago…

This is just "hur dur C undefined lol" level of a comment. If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse. If that means implementations have to ship their own float formatter and parser than so be it - no one is tied to whatever comes with their libc, package manager or no package manager.

I did say slightly snide.

But it isn't just about undefined behavior, it's more about the culture of C and how it approaches package management and sharing (or in this case, doesn't). Even if C has Rust level correctness checking it would have the same issue.

>If you are serious about your data format supporting round tripping you can and should specify the precise ASCII encoding of binary floats and the inverse.

Well I guess we have our answer in the case of seriousness. I'm guessing it didn't matter enough for the implementers, or it did matter but could never actually get it implemented. The reasons for this are numerous, contextual (with context we'll never have), and probably not rooted in technical reasoning.

We are talking about the domain of animation and games, after all. Not mission critical code. There's more wiggle room, especially for the complexity of media around when the format was being developed.

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#267

Post by sbarre »

Osiris wrote: post #239
sbarre wrote: post #238

Earlier quoted context omitted.

It's called "virtual test drive" but is it really just a turntable of a car? I tried a bunch of keyboard commands and nothing happened. Can I test drive the car?

Worked for me. I clicked drive and then drove around.

Ah, there were no buttons for me anywhere on screen, so maybe it didn't fully load.

Thanks!

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#268

Post by panzi »

bssrdf wrote: post #243
panzi wrote: post #182

Earlier quoted context omitted.

Interesting. Since the list is sorted, is the insertion still a linear search (O(N)) or now a binary search (O(log(N))? Or did I misunderstand something? Also, why is it not a hash table (almost O(1))?

Good point, I have the same doubt. Even if it is sorted, you still cannot do binary search on it unless using some skip list ideas. In fact, the code right now is doing linear search to find the ID given a name. TBH, I don't fully understand how the ID linked list is utilized in Blender and why it needs to be sorted by names. It seems some other data structure could also work, unless I missed something.

Oh is it an actual linked list and not an array?

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#269

Post by bssrdf »

panzi wrote: post #268
bssrdf wrote: post #243

Earlier quoted context omitted.

Good point, I have the same doubt. Even if it is sorted, you still cannot do binary search on it unless using some skip list ideas. In fact, the code right now is doing linear search to find the ID given a name. TBH, I don't fully understand how the ID linked list is utilized in Blender and why it needs to be sorted by names. It seems some other data structure could also work, unless I missed something.

Oh is it an actual linked list and not an array?

Yes, actually it is a doubly linked list.

Re: Pixar, Adobe, Apple, Autodesk, and Nvidia form alliance for OpenUSD

#270

Post by itishappy »

knapcio wrote: post #211
itishappy wrote: post #166

Earlier quoted context omitted.

Pixar started work on the Universal Scene Descriptor format in 2012. [0] Larimer theorized bitUSD in 2013. [1] [0] https://openusd.org/release/intro.html#heritage-of-usd-at-pi... [1] https://www.steem.center/index.php?title=BitShares:Proposal_...

I find that my confusion primarily arises from the utilization of "USD", an abbreviation denoting the United States Dollar which exists since 1792 :)

Oh, huh... Excellent point that hadn't even occurred to me!
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