well...I tried something easy and opened the "entity.lua" in "\Steam\steamapps\common\Factorio\data\base\prototypes\entity" and isolated the iron chest entry
----------------------------
{
type = "container",
name = "iron-chest",
[shortened here]
collision_box = {{-0.35, -0.35}, {0.35, 0.35}},
selection_box = {{-0.5, -0.5}, {0.5, 0.5}},
[I think 1x1 is about 1 tile of concrete (-0.5 to 0.5 is 1; 0.0 is the center of the entity) and it looks like "collision box" (where you hit the building) is always a bit smaller than selection box (the yellow markers when you hover your mouse over building)]
[shortened here]
picture =
{
filename = "__base__/graphics/entity/iron-chest/iron-chest.png",
priority = "extra-high",
width = 48,
height = 34,
shift = {0.2, 0}
}
},
This is the part I was looking for...simply doubling the height and width will do nothing but produce errors when starting factorio...width and height is the same as the resolution of the iron-chest.png. In order to create bigger entities you have to change the png size and write the resolution in the lua.
Example...
I enlarged the iron chest x5...my png is now 240x170, I adjusted
collision box and selection box to
collision_box = {{-2.35, -2.35}, {2.35, 2.35}},
selection_box = {{-2.5, -2.5}, {2.5, 2.5}},
and height/width to
width = 240,
height = 170,
and this was the result
As you can see, the iron-chest picture and the collision and selection box don't match but this problem should be solveable by either adjusting the png-size or finding the right value of "shift = {0.2, 0}"
*edit: On second thought...the box fits pretty good on the concrete tiles...adjusting the collision and selection box 0.5 to the left should do the trick
Hope that helps...Im still a bloody newb and this was my first attempt
*edit: Havn't tried animations so far...guess it's the same but different

*edit: oh and you need different *.png's and settings when you create buildings which you want to be able to rotate them...