11–20 of 28 posts
Cute but the models are not very robust
Earlier quoted context omitted.
These all look like physics engines for graphics rendering. They all say 2d or 3d, and that means they surely can't handle concepts like relativistic spacetime. Do you know of any libraries for doing 'backend' physical simulations, such as calculating scattering amplitudes, making projections of spacetime models onto either space-like or time-like slices, and, especially, using tensor networks for modelling condensed…
Writing a general engine to do all these things is likely not a reasonable thing to do. Complicated dynamical systems usually involve solving PDEs and for that you need to discretize your domain. How you choose to do so will drastically affect the numerical properties of your simulation. Most "real-physics" simulators tend to be specialized to a given task or even a given domain (for example simulating heat diffusion…
Most modern game physics engines aren't actually discretizing an ODE or a PDE, at this point. The current standard techniques (see Nvidia's PhysX, for example) are instead solving something that look like a constraint satisfaction problem but gives force-like effects. You don't even get consistency under refinement with these methods, but they are cheap, and importantly, stable when terminated early (to remain under strict time budgets required of game based physics).
Earlier quoted context omitted.
Writing a general engine to do all these things is likely not a reasonable thing to do. Complicated dynamical systems usually involve solving PDEs and for that you need to discretize your domain. How you choose to do so will drastically affect the numerical properties of your simulation. Most "real-physics" simulators tend to be specialized to a given task or even a given domain (for example simulating heat diffusion…
> The generic game physics engines use very simple models of mechanics and allow for numerical issues (e.g. by using finite differences) Most modern game physics engines aren't actually discretizing an ODE or a PDE, at this point. The current standard techniques (see Nvidia's PhysX, for example) are instead solving something that look like a constraint satisfaction problem but gives force-like effects. You don't even…
Earlier quoted context omitted.
> The generic game physics engines use very simple models of mechanics and allow for numerical issues (e.g. by using finite differences) Most modern game physics engines aren't actually discretizing an ODE or a PDE, at this point. The current standard techniques (see Nvidia's PhysX, for example) are instead solving something that look like a constraint satisfaction problem but gives force-like effects. You don't even…
Interesting. So are these minimizing some constrained energy based on the physical properties and current state of whatever you're trying to simulate? If so, I don't quite understand how you avoid solving (or approximating) a PDE/ODE. My research is mostly in meshing and I'm not familiar with real-time simulation stuff. Do you have a link to a good paper on the topic?
Earlier quoted context omitted.
These all look like physics engines for graphics rendering. They all say 2d or 3d, and that means they surely can't handle concepts like relativistic spacetime. Do you know of any libraries for doing 'backend' physical simulations, such as calculating scattering amplitudes, making projections of spacetime models onto either space-like or time-like slices, and, especially, using tensor networks for modelling condensed…
This might be of interest for spacetime modeling: https://arxiv.org/abs/1712.07658
It may be worth saying that numerical relativity played a key part in the last Nobel prize for the detection of gravitational waves.
Nevertheless it's nice to refer to this analogy.
Code and explanation: http://www.physicsandbox.com/projects/double-pendulum.html
Demo: http://www.physicsandbox.com/projects/double-pendulum-sim.ht...
http://htmlpreview.github.io/?https://github.com/aguaviva/Ph...
Earlier quoted context omitted.
Interesting. So are these minimizing some constrained energy based on the physical properties and current state of whatever you're trying to simulate? If so, I don't quite understand how you avoid solving (or approximating) a PDE/ODE. My research is mostly in meshing and I'm not familiar with real-time simulation stuff. Do you have a link to a good paper on the topic?
Check out 'Position Based Dynamics' by Matthias Mueller, it was the first paper on the topic.
[0] http://www.bulletphysics.com/ftp/pub/test/physics/papers/Ite...
cool! Included here: https://www.tapirgames.com/blog/open-source-physics-engines
These all look like physics engines for graphics rendering. They all say 2d or 3d, and that means they surely can't handle concepts like relativistic spacetime. Do you know of any libraries for doing 'backend' physical simulations, such as calculating scattering amplitudes, making projections of spacetime models onto either space-like or time-like slices, and, especially, using tensor networks for modelling condensed…