physics with grouped display objects?

Getting Started Newbie Questions
#1

From what I’ve read if I want to create a display object with child display objects I should use a group.  for example

 local cube2 = display.newRect( groupy, 0, 0, 20, 20 ) local cube = display.newRect( groupy, 20, 20, 20, 20 ) groupy.x, groupy.y = 100,100 physics.addBody( groupy, 'static' )

this is fine…  now when I move “groupy” around my display objects stick together as expected…  the problem is when I add my physics body to it.  I get a very weird physics boundary.  I’d expect it to stick to the edges of it’s contents but it doesnt.  What is going on here??

MgzvQXW.png?1

#2

This might help: https://forums.coronalabs.com/topic/59824-physics-groups-behavior/?p=309783Basically, you’ve added a body to the group, but the display objects within the group are still just displays objects - there is nothing in any Corona documentation saying that physics objects auto-update when their contents changes. If you’re trying to have the parent physics body shape change when the objects inside it move around, you will need to update it yourself. I would suggest not having them in a group at all (because of the problems that causes with display groups) and just make them bodies and join the using joints. Why do you. Want them to change their parent group’s shape?

#3

This might help: https://forums.coronalabs.com/topic/59824-physics-groups-behavior/?p=309783Basically, you’ve added a body to the group, but the display objects within the group are still just displays objects - there is nothing in any Corona documentation saying that physics objects auto-update when their contents changes. If you’re trying to have the parent physics body shape change when the objects inside it move around, you will need to update it yourself. I would suggest not having them in a group at all (because of the problems that causes with display groups) and just make them bodies and join the using joints. Why do you. Want them to change their parent group’s shape?