Whoof. I support any effort that competes with AutoDesk -- they're an abysmal company that go out of their way to encourage people to compete with them -- but you're picking quite an ambitious project here.

If you want to produce a closed-source product, your programmers will be somewhat limited in the various open source projects that they can use as an effective foundation for this.

I'd say, purely from a software development standpoint, to produce a version 1.0 of something that might have a chance of competing with Flame, you're gonna need: a good UI guy, a brilliant 3D hacker, a pretty sharp math guy (fortunately they're cheap these days :-), a good programmer, and an experienced project manager with some respectable coding chops just to keep the project moving along. So, say a minimum of $250k combined yearly salaries. If you're a strong businessman, and if you get the right team together, you might be able to get a beta released in 12 months.

That estimate is high or low depending on how much higher or lower your goals are in terms of a first release, but it should be kind of ballpark.