Hello, so I am working on designing a custom arrival that I eventually plan to add to the PMDG FMC in MSFS. I was thinking of trying to figure out the calculations for how far apart to place each waypoint from the others, so that I can maintain any altitude or speed restrictions. Then I thought that maybe I could just place the waypoints far enough apart that I know the distance would be enough, but I don't know if it's actually that easy. So let's say you have a waypoint with an altitude restriction of 25,000 ft, and the next waypoint has a restriction of 19.000 ft but is, say, over 40 miles away, which I think would be more than enough. Would there be any reason this wouldn't work from an AP logic standpoint? By that I mean that even though the waypoints are farther apart than they need to be, the AP won't start descending to the next altitude restriction until it needs to, rather than starting to descend when passing the previous waypoint, even though it would be too early.

Any advice?

Thanks

I don't know how they do it IRL but consider a 3 deg profile is 300 ft/nm, or in your case you need to descend 6,000 feet which should take 6 x 3 = 18nm.

That may help?