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Pixar's notes on Rigid Body Simulation (2001) [pdf]

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Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#11

Post by pfranz »

imachine1980_ wrote: post #8
gabereiser wrote: post #6

Pixar is one of those companies I admire. Not just because they make amazing stories, but because they make amazing tech. A long time debian user, I found renderman to be ridiculously awesome. The scale of which a frame can render across a network of random machines… Not to mention the graphics problems they have solved and optimized to bring to the entertainment industry. It’s like if mathematicians and artists were…

i'm feeling that mass production of the last year is making this lees than was before. for example i feel the best looking pixar movie is toystory 4(graphic wise, and coco graphic+art direction), current movies like red, or souls, feel cheaper being a lot less "magic feeling", and look like inside out graphics a movie from 2015(7 years), movies like encanto feel more polished and movies like the spiderverse from 2018…

My wish/dream has been that realistic tech is so mature they're no longer spectacles. I felt "tentpole" movies were getting there before Marvel kicked off. Instead the focus is either on story or stylization. I love that in Turning Red they billowing smoke will dissipate into clumping bubbles and they adopted a lot of anime styles into 3d. Effects like smoke, water, and fire are the easiest to focus on. 2d animation has done a lot of this for decades; Malificent's dragon breath, Genie's smoke, Akira's effects.

I think CG sequels, especially as far apart as Toy Story 1 and 4 (24 years!), are a unique thing. It has to be familiar and consistent with previous movies that used older tech, but they can't make a new movie using 24 year old tech, either.

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#12

Post by Stevvo »

saboot wrote: post #5
cyber_kinetist wrote: post #3

Earlier quoted context omitted.

Note that there are multiple approaches to implementing rigid body simulation (especially when it comes to resolving collisions), and each of them all have their benefits and disadvantages. For example, Mujoco uses a soft contact model where penetrations can happen, this can be undesirable for some use cases but might not really matter for most people. Mujoco also assumes every object in the simulation to be defined…

I've been implementing a 2D physics sim myself, I'd take be interested to hear more about different approaches. For example one that can handle the creation of more objects and handles friction accurately.

Some years ago I did a project with LiquidFun; https://google.github.io/liquidfun/

It was an interactive art thing for kids; had a TV with a maze of transparent PVC pipes mounted on the front with valves (rotary encoders inside). The kids would open and close the valves, and watch the flow of water be redirected on the TV behind.

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#13

Post by natly »

This is way more intricate than it needs to be. Game coders have all these old ideas floating around like quad trees and aabb collision detection which has gotten a lot of improvements over the years (a lot of which is just conceptual improvements). I really like PBD as a good alternative to the formulation linked above: https://www.youtube.com/c/TenMinutePhysics.

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#14

Post by cyber_kinetist »

saboot wrote: post #5
cyber_kinetist wrote: post #3

Earlier quoted context omitted.

Note that there are multiple approaches to implementing rigid body simulation (especially when it comes to resolving collisions), and each of them all have their benefits and disadvantages. For example, Mujoco uses a soft contact model where penetrations can happen, this can be undesirable for some use cases but might not really matter for most people. Mujoco also assumes every object in the simulation to be defined…

I've been implementing a 2D physics sim myself, I'd take be interested to hear more about different approaches. For example one that can handle the creation of more objects and handles friction accurately.

Well, it’s a pretty huge topic. I recommend taking a look at the SIGGRAPH course notes on contact and friction simulation:

https://siggraphcontact.github.io/

Also, look at some recent papers on SIGGRAPH and SCA, such as:

- https://matthias-research.github.io/pages/publications/PBDBo...

- https://mmacklin.com/primaldual.pdf

- https://arxiv.org/pdf/2201.10022.pdf

Note that these are all cutting-edge stuff, and most physics simulations in production still use more traditional methods (which you can learn from Box2D’s source code and related GDC slides). The links:

- https://github.com/erincatto/box2d

- https://box2d.org/publications/

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#15

Post by kuschku »

imachine1980_ wrote: post #8
gabereiser wrote: post #6

Pixar is one of those companies I admire. Not just because they make amazing stories, but because they make amazing tech. A long time debian user, I found renderman to be ridiculously awesome. The scale of which a frame can render across a network of random machines… Not to mention the graphics problems they have solved and optimized to bring to the entertainment industry. It’s like if mathematicians and artists were…

i'm feeling that mass production of the last year is making this lees than was before. for example i feel the best looking pixar movie is toystory 4(graphic wise, and coco graphic+art direction), current movies like red, or souls, feel cheaper being a lot less "magic feeling", and look like inside out graphics a movie from 2015(7 years), movies like encanto feel more polished and movies like the spiderverse from 2018…

Neither Turning Red nor Encanto are Pixar movies? They're from Walt Disney Animation Studios, rendered with Hyperion (just like Frozen, Tangled, Moana or Zootopia).

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#16

Post by saboot »

cyber_kinetist wrote: post #14
saboot wrote: post #5

Earlier quoted context omitted.

I've been implementing a 2D physics sim myself, I'd take be interested to hear more about different approaches. For example one that can handle the creation of more objects and handles friction accurately.

Well, it’s a pretty huge topic. I recommend taking a look at the SIGGRAPH course notes on contact and friction simulation: https://siggraphcontact.github.io/ Also, look at some recent papers on SIGGRAPH and SCA, such as: - https://matthias-research.github.io/pages/publications/PBDBo... - https://mmacklin.com/primaldual.pdf - https://arxiv.org/pdf/2201.10022.pdf Note that these are all cutting-edge stuff, and most phy…

Thank you very much! This is great stuff, I have definitely found it overwhelming.

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#17

Post by thescobey »

kuschku wrote: post #15
imachine1980_ wrote: post #8

Earlier quoted context omitted.

i'm feeling that mass production of the last year is making this lees than was before. for example i feel the best looking pixar movie is toystory 4(graphic wise, and coco graphic+art direction), current movies like red, or souls, feel cheaper being a lot less "magic feeling", and look like inside out graphics a movie from 2015(7 years), movies like encanto feel more polished and movies like the spiderverse from 2018…

Neither Turning Red nor Encanto are Pixar movies? They're from Walt Disney Animation Studios, rendered with Hyperion (just like Frozen, Tangled, Moana or Zootopia).

Turning Red is a Pixar film, see https://en.wikipedia.org/wiki/List_of_Pixar_films

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#18

Post by JustinGarrison »

Pixar is academics who use stories to showcase their technology. Disney Animation is artists who use technology to tell stories.

I worked at Walt Disney Animation Studio (WDAS) for a while and this was the best best explanation of the differences between Pixar and WDAS

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#19

Post by gabereiser »

kuschku wrote: post #15
imachine1980_ wrote: post #8

Earlier quoted context omitted.

i'm feeling that mass production of the last year is making this lees than was before. for example i feel the best looking pixar movie is toystory 4(graphic wise, and coco graphic+art direction), current movies like red, or souls, feel cheaper being a lot less "magic feeling", and look like inside out graphics a movie from 2015(7 years), movies like encanto feel more polished and movies like the spiderverse from 2018…

Neither Turning Red nor Encanto are Pixar movies? They're from Walt Disney Animation Studios, rendered with Hyperion (just like Frozen, Tangled, Moana or Zootopia).

Walt Disney Animation Studios is Pixar.

Or rather, Pixar is Disney.

https://www.history.com/.amp/this-day-in-history/walt-disney...

Re: Pixar's notes on Rigid Body Simulation (2001) [pdf]

#20

Post by wolverine876 »

JustinGarrison wrote: post #18

Pixar is academics who use stories to showcase their technology. Disney Animation is artists who use technology to tell stories. I worked at Walt Disney Animation Studio (WDAS) for a while and this was the best best explanation of the differences between Pixar and WDAS

Thanks for the insider insight. Were you there before or after Disney acquired Pixar?

Ratatouille and Wall-E, for example, weren't seen as story-telling?

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