sebcrozet
Joined 12 years ago
Karma
106
Submissions
11
Member since
Sep 14
Recent submissions
Comment · 6 years ago
Yes, it uses a Newtonian formulation. Another physics engine (nphysics) I wrote before rapier, had a Lagrangian formulation of joints (using reduced-coordinates). This is something I intend to add to Rapier too at some points.
Comment · 6 years ago
No C bindings so far. This is something I would like to consider doing at some point. Though when exactly it is done will depends on the demand since I have limited resources.
Comment · 6 years ago
The main source of inconsistency for nphysics performances is its broad-phase algorithm. It is a tree-based approach which is admittedly not written very efficiently and has very unstable performances when most objects moves.
Comment · 6 years ago
Author of Rapier here. The best way to get help would be to join our discord server [1]. There is a channel dedicated to rapier.js. So far most of us are Rust devs but we want to grow our JS community progressively.
You can also ask questions/post issues on the rapier.js repository [2]. You will also find a WIP user-guide on the rapier website: [3].
Right now the JS bindings are not complete, so a couple of months of work is still needed to expose all the capabilities of Rapier through JS.
[1]: https://discord.gg/vt9DJSW
[2]: https://github.com/dimforge/rapier.js
[3]: https://www.rapier.rs/docs/user_guides/javascript/getting_st...
Comment · 6 years ago
Yeah, ray-casting and CCD are missing currently, mostly because I didn't have the time to implement them yet (though I did implement them on ncollide/nphysics (https://nphysics.org) so it is mostly a matter of adapting/rewriting them to fit in Rapier.)
Comment · 8 years ago
Well most physics engine, including nphysics, bullet, box2d, are able to achieve much more realistic simulations: just increase the number of iterations for the constraints solvers, and reduce the timesteps length. Of course this will no longer be real-time but will be suitable for generating animations. In the end, it always boils down to a compromise between performances and realism unfortunately.
Comment · 12 years ago
Yes, the physics demo shown in the user guide was a bit slow (less than 60fps for sure). This video was made one year before today, using a version of nphysics that was at least 5 times slower than the current one.
Also, unless the gravity is artificially boosted, things may still look a bit slow because of the scale issue described by aaronetz (in all the demos, most objects are around 1 meter tall, and the camera is far enough to see them all). AFAIK, it is not uncommon on e.g. video games, to artificially increase the gravity so that things look a bit more dynamic.
Comment · 12 years ago
The one application I know for 4D collision detection is 3D continuous collision detection. If two 3D objects are moving, you can parameterize their movement through time to obtain a 4D shape. If those movements are only translational, and the two shapes are convex and have a support function, then testing for contact is easy (e.g. using GJK). However if those movements contain rotations, the resulting 4D shape will be concave so interference detection may be hard.
I do not think anybody actually uses this method though.