Irrlicht Engine

Hello.

I have a question about wich "units" are used in irrlicht.
For example: if I define a radius in an createFlyCircleAnimator i define the radius as an f32.
My question is, what do this type really mean, is it pixels???.

This may be a dumb question but if someone could try to explain it to me
I would be very glad.

I'm sure that units are whateveryou want them to be.

They can be meters, kilometers, inches, feet, millimeters, etc...

You can't really measure 3D scene's with pixels, however. If I draw a sphere with a radius of 5 in the middle of the screen, it will look much larger at 640x480 than if I drew it at 1024x768.