Pfft, 45 days is nothing. The CGI effects for Jurassic Park took on average 10 hours to render, per frame. There's about 4mins of CGI footage in Jurassic park, so that's 57600 hours (342 weeks/6.6 years!!) Mind you that was back in the day when computer hours were more expensive than they are now, these days you could afford to spend millions of computer hours for complicated effects and still achieve a short turnaround time (with a large enough bank (network) of computers of course).