do buildings need collision geometry?if so how do i give a building collision geometry and how do you reduce poly count....
here s the building im working on for tean:

Strictly speaking no, visual munge will create one from the msh if there isn't one but it may not satisfy all the collison needs, it may close off openings it shouldn't and there may be places where you fall or walk through.

The easiest collision to make is select all the model components (so all your cubes and cylinders etc) and merge them into one, (on the pop up screen move the little slider to 0 it defaults to 1 and that can cause problems on things that are close together) This will create a new mesh rename it to collision drag and drop it under the dummyroot and press H to hide it. Also if there are doorway or holes in the wall you will probably need to make a .option file for the exported msh and this should be in it:
-donotmergecollisions

This will stop munge from blocking the holes as it sometimes likes to do.

As for how to reduce polys, select the item you want to reduce, go to Model/Modify and select reduce polygons.
Once again there is a slider if you move it back and forth you can vary the degree of reduction.

... he he eh... the poly thing . i was looking in every other tab than modle... yay my bad..
oh but ty for the great and helpful answer.. but i am haveing one prob... the model tab i s grayed out
[img]I%20AM%20HAVEING%20TROUBLE%20GETTING%20THE%20RIGHT%20IMAGE%20TO%20UPLOAD%20AT%20THE%20MOMENT[/img]
but i am haveing one prob... the model tab i s grayed out

Yeah same for me too...And since I am reluctantly using Reps MshEx, I wanna make sure I dont have too high a poly count

i figured it out... its under modle/modify/poly. mesh/polygon reduction that s how..