In ECO-engine the spaces height is inherited from the height of the building block. To model a spaces with multiple heights follow the steps bellow:

 

1. Draw the blocks with multiple heights

 

2. Navigate to the wall parts of the structure level of one of the two blocks, to select the common wall part between the blocks.

In the properties tab set the Is virtual property to Yes.

 

 

3. Merge the two spaces as show here.

 

The two merged spaces are now consider as one. The height of the zone used  in the calculations is the mean height = (height1+height2) / 2.