Sizes of objects in units

[minas1]

Alright, so I have loaded a 3DS mesh (a wall) and I got it to be displayed.
However, I had to set the camera's position to (0, 150, -200) in order to be able to see the whole wall, which is at point zero.

Does this mean that the mesh it too big, and I have to change its scale to something less than 1.0?
Or do units have no significance at all? (When used with lights/shadows for example)

In other words, what should be the size in units of a small mesh? Let's say a mesh that represents a dog.

[kklouzal]

My scale is (1.0F == 1 Meter)

[hendu]

The scale is your choice. Commonly 1 unit = 1 meter like kklouzal has, but you can use feet, mm, or whatever.

[minas1]

Thank you. I will use 1.0f = 1m as well.
Another thing: How can I get the dimensions of a mesh in units?

[CuteAlien]

The boundingbox gives you the dimensions (or well... the best approximation you can get with a box).