Does size matter? ;)

Hey blenders, this is my first post here…

I want to create a game in the BGE. I have modelled the main character and am about to start the rigging process. During modelling I have resized everything multiple times. My question is: How big is a good size to resize my character to now? How big should he be in relation to the default cube for example? Does it even matter? I want large levels if that helps.


I don’t think the size matters that much unless it’s very different. for example if you have a character that is 5 blender units and one that is 20 blender units and you have a near sensor with a value of 1 it won’t be the same distances with 5 and 20 blender units. if you want you can just go to the scene tab > units > and change it to imperial so you can see how big it is in feet or inches to get roughly the same size as in real life. Again i’m not quiet sure if the sizes actually matter.

Thanks Blenderman, never knew about the imperial measurements. Very handy. I thought I would have to UV map a ruler/measuring tape! lol

e2a I will use the imperial measurements and have the character at 6ft tall. I figure blender can only zoom in so far (although it seems very far)

The size matters if you use physics.

1BU = 1 metric meter.

There are also some default margins that might be visible when the objects are very small.

Beside physics I can’t see anything that can’t be scaled to any dimension.

Cheers Monster. I do intend to use physics so that is a great help.

Monster:Please, what is the better?use small or big models for better physics?

For physics, there’s a limit to respect. For better (accurate) physics, it’s a good idea to double the scale [1m =2BU]. Too small, and collisions will be wrong or not happen properly. Too big, and you’ll have a map problem: if your character is 10 units tall, and is acting somewhere in the margins of the scene [default= 1000BU], calculations will lose accuracy.
But for almost any “legal” size (determined by the bounding box size) you can tweak it to behave almost as you want!
So it’s up to you!

I´d like an idea-I sometimes (as character) fall under the scene(ground mesh), so is there any “scale” problem, or is it normal in blender?

It happens, if the character is too small. You can fix it by changing the bound box type, or increasing it a bit. I found that 0.01 is the min, but it works better from 0.015 (0.02)…

Thanks. I will make him 4 BU tall = 2m in “real life” then (for the purposes of my game)
So if I go smaller than this then the collision detection will suffer? Thing is though, I wanted to use real physical bullets in this game, which obviously will be much smaller. Surely I don’t have to make the bullets 2BU across?! Sorry for noobish questions but I am a one :stuck_out_tongue:
Thanks for the help all very good info :slight_smile:

4BU = 4 meters!

If you want to use larger objects you need to scale the gravity up as well. There is a difference if an object falls from 1 meter (BU) or from 2 meters (BUs).
But this depends on the type of game. Maybe this is what you want. A kind of art thing :slight_smile:

If you want to use 4 BU for 2 meters, change “gravity” to 19.6.

For very small, fast-moving objects like a bullet, for the sake of your calculations you can generally safely assume they are small enough to have functionally no volume- which means you can easily have them move incredibly fast with good collision accuracy by removing physics and then in python calculating where they will be based on their velocity, gravity, and factors such as wind if you want to include those, and cast a ray from where they are to where they will be- thus ensuring it will, with perfect accuracy, strike any surface between those points.

You can also reduce the velocity and continue its motion, if you want the bullet to penetrate surfaces such as glass or very thin wood.