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News & Dev

Performance Enhancements

March 8, 2018

Ello’ Zomboids and Zombettes. Some cool stuff to talk about this week!


Today we released public vehicles build 38, which is a general fix/polish update while the more structural optimization work detailed below has been running in parallel. You can find the changelist here.

Items of note include an improvement to vehicles clipping over each other – although to eradicate this completely will require structural work on a depth buffer, and more importantly the rewritten 3D model system that’s a part of future animation builds. This said, this build should at least see a marked improvement.

Other bugs fixed that’ve proved an irritation to testers include far more satisfying zed/vehicle collisions in MP, key loss lessening, a limitation on the threat of invisible trees and the removal of in-car 3D sound to make the sounds less disorientating.


Despite a lot of work and improvement over recent builds, for a little while we hadn’t been satisfied with the performance in our vehicles beta. It was workable, and clear that testers are having a lot of fun with it, but not something we felt was good enough.

As such over the past couple of weeks we’ve been working on what we feel are rather special and significant optimizations – basically going through every area of the game code and shaving off every millisecond we could, and the results have been quite profound.

On our internal test PCs (fairly good set-ups) it’s now possible to obtain a solid 60fps when zoomed out at almost every point in the map, save for the mall and downtown West Point – which regardless are themselves a lot more playable now.

The following video is shot in 1920×1080 and shows the improved performance we’re seeing on standard settings. Note the FPS read out in the top left. We thought about editing together pieces from different tests, however felt that cutting between them may look like sneaky editing, so have opted to use 5 minutes of uninterrupted recorded footage from two runs.

This video is recorded in 3800×1600 and shows the sort of performance you could expect on much higher resolutions. Hopefully not that much different from 4k framerates:

Additionally, as you may be able to tell from the videos, we have also added support for uncapping the FPS into the game options, now the FPS has improved significantly to make use of it. Hopefully this will make those with high refresh-rate monitors happy. Internally we have hit 300+ fps when zoomed in in low density areas of the map with FPS uncapped, which is pretty nice and silky on a 144hz G-Sync monitor!

We had hoped this optimization build would have been ready to release today, but when doing such deep and all-encompassing optimization that touches on many areas of the game, there are always new unintended side effects and new bugs introduced from changing the code to make it faster. Aspects of the UI suddenly become unhinged by the frame-rate, lighting refreshes go wonky etc, as well as some more serious issue of invisible items being dropped on the floor and a few others that sadly meant we couldn’t push it out today.

As such we decided to release the existing changelist of Vehicles Beta 38 and leave this until next week, when there’s a few less gremlins in the system. We hope this will then be the candidate for moving vehicles into our established IWBUMS beta as we step up plans for animations etc.


As mentioned previously, alongside the animation systems that Bitbaboon Mark is prepping, we have a few other new systems to drop into testing once vehicles are out of the way.

The first is Stas’ new chat window and functions for MP, and the second, meanwhile, is the new snog/fog that will come hand-in-hand with a general improvement/deepening of how weather works in-game. This all comes from Turbo, once a modder and now a valued contributor to PZ, who generally sits aside from the main team cooking up crazy/intricate concoctions that can then be passed on into the main game.

We should have a full time-lapse next week, although existing fog vids live here, but for now you can see how it all works on Turbo’s debugger. Right now we only have a single daily temperature, precipitation values etc, but now an extra layer on top of the existing climate system will have more varied weather/temperature change throughout the day – and also more realistic weather systems over multiple days.

So a quick example, here you can see a foggy day – in which the sunlight is a white line. Here you can see the light blue fog line building up in the morning, just before the sun rises, after which the sun has rises and the in-game fog starts to fade away.

Meanwhile over longer periods, rather than it feeling rather random, precipitation will be clustered so you can have lots of days without rain and then a longer period of days with a lot of rain/snow.

As you can see from the following picture, the climate modelling goes much deeper than that though, tying temperature, wind, and other factors together into a pretty deep system worthy of Project Zomboid:

This week’s zed race from JoeScore. A general list of stuff added to PZ, and vids of features being worked on, is kept here – so you don’t have to plough through endless dev blogs for info. The Centralized Block of Italicised Text would like to direct your attention to the PZ Wiki should you feel like editing or amending something, and the PZ Mailing List that can send blogs like this and patch notes direct to your mailbox. We also live on Twitter right here! Our Discord is open for chat and hijinks too. Fanks!