relationship between eye height and collision body in UDK

| | August 8, 2015

We are using the UDK in a research lab setting so we must understand exactly how tall users feel in the virtual world (camera position). By Googling and digging through code, we have discovered the BaseEyeHeight parameter and also the dimensions of the collision cylinder (CollisionHeight). We attempted to set these using Remote Control and could not deduce the relationship between the variables.

For one thing, it seems that BaseEyeHeight has a ceiling. We cannot set it arbitrarily high but the height that is allowable seems to be dependent on the height of the collision cylinder, though it can be higher than the cylinder. Is there a ceiling for the eye height?

Secondly, the height we set for the collision cylinder does not seem to match the height of an object in the world that should be the same height. Is the collision cylinder in the same units as the rest of the world? Is there some padding that I am not accounting for?

Finally, BaseEyeHeight does not seem to be the height from the ground. I read somewhere that it should be the height from the center of the cylinder. Is this true? I would expect the eye height to be a bit lower than the actual collision height (as in the real world). Is this the case?

The big picture problem is that we cannot find a diagram or detailed description of how these numbers relate to one another. Is there a comprehensive source we’ve missed?

One Response to “relationship between eye height and collision body in UDK”

  1. The cylinder height property is the distance to the center of the cylinder, so it is actually half the total height of the cylinder. The eye position is BaseEyeHeight above the center of the cylinder, or cylinder height + BaseEyeHeight above the ground. Also, the cylinder floats about 2 u real units above the floor, so add that in to be really precise. The UDK forums at are a good place to ask this kind of question. Also, check out the UDK documentation at .

Leave a Reply