why cant i called 2 physics at a game bug?

Getting Started Newbie Questions
#1

when I called this two function and add different body with it, it seen to react only to a physic.Bug or restriction to only 1 physic

[lua]local function loadPhysics()
physics = require(“physics”)
physics.start()
physics.setGravity(0,9.81)
end

local function loadWoodPhysics()
woodPhysics = require(“physics”)
woodPhysics.start()
woodPhysics.setGravity(0,15)
end[/lua] [import]uid: 40786 topic_id: 11898 reply_id: 311898[/import]

#2

Not a bug; rather a “restriction to only 1 physic”, as you put it. [import]uid: 52491 topic_id: 11898 reply_id: 43429[/import]

#3

Gravity is global for all physics objects in a scene and cannot have multiple values. You can change an objects physical properties (density, friction, etc.) to get them to react the way you want. Check out the physics documentation for details.
http://developer.anscamobile.com/content/game-edition-box2d-physics-engine
http://developer.anscamobile.com/content/game-edition-physics-bodies
[import]uid: 27965 topic_id: 11898 reply_id: 43432[/import]

#4

thanks for the info…!
btw I tried applyforce to a group object but the force apply to the object seen to be different from the applied x and y position. Where is actually the center point of grouped object. [import]uid: 40786 topic_id: 11898 reply_id: 43511[/import]