mdlMinDist_betweenElms to get elements with a distance less than 600 mm?

I am currently trying to find a way in VBA to identify cells where the distance to the next cell is less than 600 mm.

In MDL-help I found the function "mdlMinDist_betweenElms" which sounds quite perfect for me - the only problem I have is that I have not too much knowledge in MDL ...

The function "mdlMinDist_betweenElms " asks for 3 inputs:

MSElementDescr* edP1 IN first element
MSElementDescr* edP2 IN second element
DPoint3d* closestPoint IN point close to minima

I got this function running but I do not know what the 3rd input (closestPoint) means.

Can someone help me?