Видео

This is static resistance with a constraint, so it can work on ramps. The resistance scales based on the contact normal forces and the radius of the shape.

I was testing Box2D and found this pleasant effect. Details: - the outer circle is static - the spinner is a motorize dynamic rigid body on a revolute joint - the spinner has 4 times higher density than the small rigid bodies - the motor torque limit is quite high - continuous collision is needed to keep bodies from leaking through the outer circle - friction is very low to keep the spinner fro...

Testing explosions that use projected area (perimeter in 2D). Gravity is zero and the bodies are connected to ground using soft weld joints.

I made these demos to celebrate the launch of Box2D version 3.0. All demos run in real time using an 8 core Ryzen CPU and maintain 60fps or better. All moving objects are fully simulated rigid bodies. You can get the Box2D version 3.0 code here: github.com/erincatto/box2d Read more about the release here: box2d.org/posts/2024/08/releasing-box2d-3.0/ Thanks to Lisa Catto for editing this video!

Card House rigid body simulation using Solver2D. github.com/erincatto/solver2d box2d.org/

Extra iterations for solvers that have fewer constraint loops, so all solvers loop over constraints the same number of times. Follow up to: ruclips.net/video/sKHf_o_UCzI/видео.html Blog post: box2d.org/posts/2024/02/solver2d/

In this video I go over Solver2D results in detail. Find the blog post here: box2d.org/posts/ Github repo: github.com/erincatto/solver2d 00:00 - Intro 00:31 - Parabolic Arch 03:56 - Confined Circles 07:44 - Double Domino Effect 09:41 - Friction Ramp 13:13 - High Mass Ratio 1 17:34 - High Mass Ratio 2 20:18 - Overlap Recovery 24:17 - Large Pyramid 27:57 - Ball and Chain 32:54 - Joint Grid 37:48 ...

This compares seven constraint solvers on a pyramid with a base of 100 boxes. A small number of iterations are allowed: 4 primary iterations and 1 secondary iteration.

Incremental greedy edge coloring to identify independent sets of constraints. There is a limit of 12 colors, starting with ROYGBIV. The outer box has many constraints, so these go into an overflow color (black dots).

Joint stability improvements for Box2D v3

box2d xmas tree

Added a dedicated test for the dynamic tree. This will help with future optimization work.

New distance joint: - separate minimum and maximum lengths - spring/damper - limits are predictive

This shows the unrealistic motion you can get when leaving out gyroscopic terms from the rotational equations of motion.

Ghost Collision

Convex Decomposition

Predictive Limits

Bending Constraint Test 1