Last Thursday, Friday, and Saturday I spent the mornings in conference call with the director and a couple producers. This is the first chance the director had to provide feedback so there was naturally a fair bit of it -- though I didn't have to wholly scrap some 20 pages and rewrite them like the most recent draft.
One thing directors bring with them is a better understanding of what they can accomplish given the budget. Since they've also worked with some effects companies, they have a better understanding of which effects are affordable. For example, I had an early scene depicting a relatively low-tech version of a lab, thinking that would be cheap, but the director's going to make it look much more spiffy. I was also under the impression that makeup effects would be more affordable than CGI -- and that's not always the case since makeup eats up a lot of shooting time.
Another factor to keep in mind is lighting setups. A movie occurs at a number of locations and one of the real time killers is setting up the lights in each location. In this case a location means a room, or hallway, or closet. So being able to shoot in the same room a few times can really save some time.
Because no-one wanted to sit on the phone for 9 to 10 hours we split the discussion up over three days. This helped because I could then spend the rest of the day doing the editing -- most of which went quickly. From what I understand the following rule is true of a large number of things but it struck me as even more true in writing (probably because that's what I'm doing): 95% of the work takes 50% of the time and the other 5% takes the remaining 50% of the time.
A fair bit of the rewriting is just going in there and figuring out the logical consquences of a change, or modifying the tone of a section. Moreover, after talking with others, one typically has a burst of new ideas, and those all flow pretty quickly. But there are some parts of writing that just need inspiration -- you can help this along by continually turning over the problem in your mind and engaging in different activities, but it still takes time. My technique is to make sure I've gotten all the parts that don't need inspiration out of the way, sometimes getting a few bits of inspiration while I'm doing that, then going back to the difficult bits. The last 5% isn't hard work -- I get a lot of walking done in that phase -- but it is time consuming.