When watching TNG episodes, it looks to me like they are computer-animated, something that I thought was a bold move, because computer-animation was so new in 1987 when they started the show (or was it 88?) Im also impressed with the learning-curve, it seems to me like the scenes from outside the enterprise are improving greatly in quality during season 1.
But when I watched the extras they said that it was all non-digital, and the extra-effects dude talked about how they had used different non-digital tricks in order to create some of the different things like stars, radiation hitting the shields, and other things happening outside Enterprise.
So is the Enterprise and the other ships in the next generation models hanging from strings like in the original series? It looks digital to me, but with more lights and detail. If Enterprise is a model-ship, it is probably a very big model.
Also (even though its slightly outside this sub-forum) Im wondering about the same things with Voyager. The effects are much better there, but on some close-ups on different ships it looks more like models then computeranimation.