Cutting holes in meshes

Hi there,

I am wondering how holes can be cut into any mesh without using Boolean Operations and without leaving any errors in the resulting object.
For now I am working on a dinosaur's skull which has some big holes like eye sockets, nasal cavities and sinuses. For the first try I cut out some polygons and smoothed the edges around the new holes. The problem is that the mesh is not closed any more which leads to some errors later on. There is just a "Nothing" instead of a correct modelled border.
What would you suggest to do? I would be glad to see you guys giving me some hints.  ;)
By the way, I am using 3ds max 4.

Thank you in advance, bye,

Noryx

Hi again,

after no one replied to my post here I also asked my question in another forum (cgtalk.com) and got a great hint.
I was told that I should try to work with the "solidify modifier" (You can find it on http://max3d.3dluvr.com.).

I hope I could help somebody out there.  :)

Bye,

Noryx

Polygonal Modeling is easier but not so accurate.
You could try cutting and deleting faces to gain more control over your model.

I think NURBS are a much more accurate and easier way of modeling orgainic shapes. with a good level of control over your geometry