"Rules" in art aren't so much rules - as in you MUST do this - as they are observed similarities between pieces of artwork that generate pleasant or desired responses in their viewers. These similarities have been observed and codified into compositional guidelines.
The "rule" of thirds or "golden mean" are tools which have been shown to create a desired effect in the viewer - keeping their views within the piece or drawing their attention to specific elements.
Of course they can be disregarded, but invalidating them because of a knee jerk reaction to the word "rule" should definitely be avoided. They are tools used to better communicate with the viewer. Disregarding them may be sometimes necessary to the effect you want to create in the piece, but - by far more often than not - they aid the work and it is best to know them and their value than to decide that, as one is an artist, they should not follow "rules".
This is posted only as a general observation over years of visiting photography and other art forums in which I have seen so many people proclaim their skill an artistry such that they do not need to know any "rules". To me, as a photographer, it's akin to saying that you don't need to know the tools of exposure, depth of field, lens selection, the effects diffraction, flare, sensor bloom, the effects of shutter vibration at key speeds, etc., etc. The rules of composition are a tool. The more tools you know and can use without thought, the more unfettered your creativity will be.
I recently saw in a Lightwave video that they have begun including compositional overlays in the camera view - I think this is an addition of another great tool - and it would be a great idea for Terragen to do something similar.
Ignore them when called for, but definitely get to know the "rules" of composition so that you can know WHEN they will not aid in the message or effect you are striving for.
Regards,
Micheal
