Goknub

If you consider the world as a "realistic" outcome of whatever happened then the lack of deer could simply be down to a lack of time to breed up numbers. Looking through the buildings you find almost no contents, not in a "picked over by survivors" way but in an "virtually everything" way. Couple this with the lack of vehicles and it could more accurate to assume that the majority of the population has actually been evacuated rather than died of disease. The level of decay would also indicate that not too much time has passed since the human population left. This would leave insufficient time for a native animal population of any kind to expand by the time our survivor rocks up on the beach.

Hi, it may be too late in the development cycle to create this but... Suggestion: Create fog banks of variable size that move across the terrain. Within these spawn large numbers of Zombies and have them follow the fog bank and/or increase the spawn rate within that area and have them remain after the fog bank passes. The idea is in the same vane as seen with the Whitewalkers in Game of Throwns. Why: I see this assisting to resolve several issues. 1. Reducing system demand as the larger, high-density groups are limited to fog banks rather than being global. 2. Broadening player skill level accessibility, larger Zombie groups that challenge skilled players will drive new players away from the game. Being able to avoid these larger groups by fleeing the fog allows new, inexperienced players a chance to survive. 3. Active world - Something to fear. Rather than the world being largely passive, the approach of a fog bank would be something to fear and being caught unexpectedly in one would allow even the most experienced player to feel a level of panic. Flee or hide? Thoughts...?

The intent of the fog-based swarms is to make give the Zombie threat some added depth and mystery. It's to give the world a bit more character and make it more active, it's the threat of being caught in a blizzard but with extra bite. The zombie threat becomes a bit generic after a while and I'd like it to have a more menacing and unpredictable nature.

Have you tried linking multiple (3ish) zombies together as one single entity? This would reduce the load on the system somewhat as only one AI routine would need to be calculated along with some other calculations. This would only work in larger groups as the effect would be too obvious in smaller ones. A mix of grouped walkers and single runners would provide for a suitably large, threatening swarm while reducing system load. Creating a reduced detail "swarm" zombie would also help, as you mentioned those polygons add up. Perhaps even a single object that is a "3 swarm zombies". Ultimately the ability to create server-wide swarms is very limited. Hence why I think a fog bank could be a useful solution. The fog effect hides the true number of zombies, keeping the player guessing and allowing less detailed zombies to exist. Alternatively it allows for a smaller number of more "intelligent" zombies, a level 3 zombie if you consider walkers lvl1 and runners lvl2. Something closer to an animal predator. Even the most seasoned and well equipped player should fear getting caught.