Invisible platforms?

[mango]

In WC3 it was easy to create the effect of making multiple story homes and buildings; you could create the building completely out of doodads and add invisible platforms and pathing blockers to direct units up stairs and though the structure. My question is: is this possible in SC2? I haven't been able to find any kind of invisible platform, but I remember in the early beta stages of the SC2 editor that Blizzard was bragging about the editor having fully 3-D pathing capabilities. Any work-arounds or suggestions are much appreciated!!

 

[Dr Super Good]

Invisible platforms and pathing blockers are supported. Weather there is an invisible platform model in SC2 is another question (a model which has only a collision geometry for walking on).

I am not sure about the full 3D pathing as it does not appear usable in normal GE.

 

[mango]

Thanks a bunch for the response!