All I know is the HT (Hierarchy Tree) is built like this:
World
Model
Objects
Str0
Object Name
In the blender we have to make a Hierarchy tree similar to this:
+1 model, MaxDist=20000
+1 objects, MaxDist=20000
+1 str0, MaxDist=20000
- objectname, MaxDist=20000 NoCollide=0
The "MaxDist" is a "Property tag", it explains from what distance you can see the object. A precise description of all possible tags is in the "ac3d.txt" file, all I can tell and show you is examples, because I do not use AC3D.