I tend to make a lot of small patches which is great for keeping everyone up to date on what's happening. The past few days I've been working on a bit more heavy changes that still need a little time to hammer out. The good news is I've already boosted performance a fair amount and added in a number of user experience improvements.
For one, I've greatly reduced the lag spikes caused when new terrains come on. This was largely caused by Unity's built-in grass system, which most people agree is pretty horrendous. Last Spring we dabbled in a fancier system that was still just getting started and proved to cause more stress on lower end machines than it did improve things over all so it was removed. That system and Unity's abilities have grown quite a bit since then, and it's working much better now. I'm still not using it for trees, rocks, and what not, but for grass it's a big improvement. Of course nothing works out of the box when you're building a world 2 million kilometers squared, but nothing a little duct tape couldn't fix.
New grass on the left, old grass on the right. The major benefit is the reduction in lag when a new terrain turns on, however it is slightly more GPU work for slightly less CPU work. That means that people on graphics cards more than a few years old may see a slight reduction in performance while just running around, but still less lag spikes. The options to turn grass down and/or off will of course remain available.
I've also ditched the "forest" method of tree spawning, where a spot is picked then a 100 year forest is simulated outward from that position. It looks nice, but it can also create large areas where nothing at all grows, and has a tendency to bleed over into areas it's not supposed to. I've replaced it with a simpler approach of noise based placement.
This and more will be heading to the beta soon after which we'll take a day or two to polish so we can push the new tutorials and everything else since added onto the live branch.