Bridge Game

Overview

A little project to play around with the Finite Element Method.

Start by drawing a bridge. The grey blocks along the side are immoveable and anything touching them will also be fixed. During the simulation, green blocks have little to no stress, red blocks are being stressed and black blocks would be destroyed (with a config flag they would be removed):

Prerequisites

MacOS

This is the platform I've been testing on, so it should "just work". Try:

brew install bazel
bazel build :main

Linux

This should mostly "just work". Make sure to install xorg-dev though for X-11

sudo apt-get install bazel
sudo apt-get install xorg-dev
bazel build :main

Control

To run:

bazel run :main

The UI should launch and will allow you to:

• Click to draw a brick
• Control click to erase a brick
• Press z to increase the cursor size
• Press x to reset the cursor size

When you press the space-bar, the simulation will start. Bricks that are under too much stress will be destroyed. Pressing the space-bar again will go back to building mode.

Python Testing

There is a python testing utility in python/testing.py which simulates a simple structure and saves off images of the displacements. Run the following commands:

rm /tmp/*.png; python3 python/testing.py
ffmpeg -framerate 30 -pattern_type glob -i '/tmp/*.png' -c:v libx264 -pix_fmt yuv420p /tmp/out.mp4 -y

Then view the video at /tmp/out.mp4. This also produces /tmp/00_init.png and /tmp/00_steady.png which show the initial configuration and steady state solution.

Notes

• The game is a work in progress without too much testing, so your mileage may very
• I haven't tested on other platforms besides my Mac

TODO

• Pause simulation
• Damping but have freefalling triangles look good
• Road with car driving on top
• Click on a triangle and see per cycle info on it

Sources

[1] http://www.unm.edu/~bgreen/ME360/2D%20Triangular%20Elements.pdf

[2] http://web.mit.edu/kjb/www/Books/FEP_2nd_Edition_4th_Printing.pdf