A big thank you to everyone supporting the development of APC.   Your contribution is greatly appreciated and definitely helps to bring APC to its full potential.  Version 0.20 has a lot of improvements, both in the physics engine and the editor.  The circles within circles example is probably the most complex game created using APC so far.  If you are planning to develop your own simulations or games using APC, please do offer any feedback or suggestions (good or bad).  

New features:

• fluid simulation based on particle pressure
• PNG image particle textures
• particle signalling
• reaction based call-out text
• pivot tool for creating hinged connections.
• shrink tool for rigid bodies
• select by particle type
• reaction driven checkpoints (snapshot and restore)
• porous rigid bodies
• fast zoom
• two new element shaders for play initialisation and per frame processing
• sound management menu
• positional audio

Enhancements:

• improved particle / rigid body collision and static friction
• new 'always' particle type for reactions
• improved control settings for rotation, thrust and impulse movement
• collide/react and apply force to particle groups
• improved audio processing for thousands of particles

20 example projects:

• angry_car
• ascii_fireworks
• bottle_flip
• car_on_a_rope
• chaos_test_x4
• circles_within_circles
• collision_test
• fluid_explosion
• fluid_mixer_test.
• frubbles
• lava_and_water
• led_display
• light_fantastic
• newtons_cradle
• psycho_lava
• rigid_car_test
• signal_lightning
• the_big_bang
• the_bucket
• tractor_challenge

Under development:

• 4 player multiplayer with separate objectives and scoringrigid deformation via reactions
• improved particle signalling
• improve rigid body stability for dynamic joins / breaks
• spawn particle structures
• particle biology with dna blueprints
• animated particle textures
• icon based gui
• controller support
• Steam workshop / achievements

Planned:

• The third dimension.

GUI alterations:

• You now use Tab/Esc to enter/exit play mode and Shift-Tab to pause/resume edit mode.