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Hurtworld Update #35


This week I’ve been working on the vehicle system and adding an all new vehicle type, motorbikes!
It’s still in its early stages so you’ll have to forgive the programmer art and the use of the goat rider animations that don’t quite fit but here’s a peek at whats to come.

I’ve been working hard to find the sweet spot between simple arcade style handling and full physics simulation.
Due to our low minimum specs and our authoritative server netcode (where the vehicle physics all run on the server to ensure consistency and stop cheaters) we need to be as efficient as possible with our simulation which pushes us more towards a basic arcade style. On the other hand the large open world, player built housing and the SDK throw a huge variety of situations and terrain at our vehicles and if we go too far in the arcadey direction then there will be too many edge cases and strange situations that the physics will not be able to deliver a satisfying simulation for. This point cuts both ways however as full on simulations generally only work well in specially designed racetracks.
Another consideration is our control scheme, the current ‘wasd’ + mouselook system only gives 1 digital axis for steering which doesn’t allow for a lot of fine control, again steering us more towards an arcade model.
I’ve developed a semi-automatic balancing system that applies a torque to balance the bike towards a target lean angle. This lean angle is influenced by the speed of the bike, previous lean angle, the camber of the ground and the player’s steering input. With the right tuning this gives some nice behaviour where you can lean further into banked corners  This system is also cheaper computationally than the cost of simulating another 2 wheels which I’m very happy about as I was worried our requirements would force us to have leaning as just an animation on top of the physics layer.
Whilst it still needs some tuning and still has some edge cases I need to iron out, we get some nice physics that behaves well and is fun and interesting to play about with just ‘wasd’.

I’d love to get some feedback about what you’d like to see from motorcycles in Hurtworld as well as feedback about our vehicle system in general, I’ve posted up a thread on the Steam discussion forums here so please jump in and let me know!


More progress on ItemV2. This week I’ve been mostly focusing on how we synchronize equiptment state machines on proxy players (players you see that aren’t you). This is a slightly different problem than the server and your own player, as both the server and your player have all the information they need to drive the simulation on their own without help. On the proxies, they have no knowledge of input controls, impacts etc and therefore need some extra information sent to them by the server to ensure they stay in sync.

In our current system, you might notice things like shotguns being shot at you making a fire sound at a different time to you taking damage / dying, or players not looking like they are aiming at you when they fire yet still get granted a hit. This is usually caused by deficiencies in our architecture for synchronizing player proxies.

There are a few possible approaches here, the main challenge is sending as little information as possible while keeping everything in sync. The more frequently we send updates the higher load on the server bandwidth and more chance of lag / less things overall we can do per server. The second challenge is building a sync layer that doesn’t require custom logic to be written on a per item basis like we did in the previous system. If we can synchronize transparently without knowledge of the item or specific scenario we are catering to, modders will have complete freedom over how they use the state machines and have to do very little work to ensure everything connects up nicely. Thinking about how things are networked is tricky, so the less of that everyone (including us) need to do in future the better.

The working solution

The solution I am working with currently is running a full state machine on the proxy, progressing state positions based on things like attack speed, but not executing any transition or event code. Instead we serialize a very efficient byte stream from the server of when and where a transition happens. As there are only ever a few possible targets for a transition, and the movement updates are already being sent with time information, we can compress the transition and event data to only a couple of bytes per transition. This adds up to a negligible amount of data while ensuring that everything stays 100% in sync.

Fast Firing Weapons

The next part of the Item system I’ve been working on this week is ensuring we can handle sub frame events. More specifically, if a gun is firing at 17 times per second and the game updates at 20 times per second, that we don’t get a stuttering mess. Currently we can only emit events on each update tick, meaning we can either chose to fire now or wait until the next tick. If we are exactly in sync with the update rate (10hz or 20hz) everything works fine. If we want to update at 18hz, we would require a timespan between bullets of 1/18 seconds which could never sync up with intervals of 1/20 seconds. What you get instead is stuttering bettween 1/20 and 1/10 seconds (similar to if you have vsync turned on and can’t get 60fps).

The solution to this is part of state machine design, where events can be emitted from the state machine with an exact time delta from the state of the tick (tick being 1/20th of a second). In effect we do partial ticks for the equipment system then store the resultant events that are emitted in a time accurate buffer to have their sounds (and possible visual effects) played at exactly the right rhythm at any frequency.

This is 90% working now, I am lastly figuring out the best way to try to give the sound event information to Unity slightly ahead of time so laggy machines have time to get the audio buffer ready and won’t miss a beat.


While this is probably overkill for your average survival game, we are doing our best to raise the bar to what is expected from other shooters. I think its worth the extra time to get the foundations right as we have with many other gameplay systems. Better gun play is never going to be a bad thing.

You guys are amazing..

We’ve been constantly blown away by the awesome stuff our community has been creating with the tools available, hence why we are working so hard to give you more powerful ones… We just stumbled across this today, which I would have probably told you this wasn’t currently possible without client side mods. But it looks like the creators found an old unfinished meteor prefab in our assets and fixed it up and completed it.

You can download the mod for oxide here:
Meteors for Hurtworld | Oxide


I am filling up the building interiors with low geo items that you would expect to find inside office buildings. I have a couple of different coloured sets of office cubicle walls, lobby desks & those couch bench-a-muh-jigs. These help create hiding spaces for fire fights, occlusion & to place loot crates or other items behind.

It takes time to place these due to the individuality of the building shapes and trying to move the items around in each building to create difference.

StreetLevelDecor_0001_Layer 2 StreetLevelDecor_0003_Layer 5 StreetLevelDecor_0002_Layer 6 StreetLevelDecor_0000_Layer 3

I finished off adding in the shop fronts also. These have large windows that actually span two floors in height now.

StreetLevelDecor_0004_Layer 8 StreetLevelDecor_0005_Layer 4


Not a whole lot from me this week as I have been bouncing around on this smg testing a few things. However I now have an in game mesh built with its normal map and ambient occlusion all baked out. Next up is to paint up its diffuse and spec maps. If I want something to be heavily damaged and worn I will usually take it into a sculpt program, scuff it up, and bake it out. but when the damage is lighter surface level damage I tend to just generate a normal map from a height map that I paint up at the same time as the diffuse. In the case with this smg I will be going more a lightly scuffed up look.



I’ve mainly been working on getting the modding stuff done and out. I’ve created a new branch for the Hurtworld SDK called “experimental”, that anyone can switch to on Steam. Check it out if you want to get a head start on creating some awesome construction packs! I’m working now on some documentation for the SDK, as the construction system can take a bit to get your head around.


I managed to tackle the main restriction on the construction system, which I previously mentioned: custom construction attachment types. Each construction attachment has a collection of attachment points where other attachments can connect, and each of these points has a “type”. For instance, a wall piece has a “floor” attachment point at the top, so you can attach a floor to the top of any wall. Before we just had a list of types that both the client and the server knew about beforehand, and that never changed. But I wanted to give the option for mod makers to make their own types, and not be restricted by ours, so we had to move to a dynamic system where mods registered their custom types, in a way that the client and server can agree on. Mod makers can also now cooperate and create common custom types shared between mods, as they’re just based on a name. Also, as a server can choose not to load the default construction pack, and we include the default construction pack assets in the SDK, it is possible to include custom attachment types in the default pack by rebuilding it.

For the next week I’m on documentation, although I hope to get it done sooner rather than later. While documenting I might find some issues that need resolving, but once that’s all done we’re ready to go! We’ll just need to push out a client/server patch with attachment support, and configure the workshop so it’s a bit more organised.

Check out the documentation here. And I’ll be answering any questions relating to the system here. Enjoy!

Hurtworld Update #34


So some more character work and some weapon stuff from me this week. Having blocked out some character forms I needed to wait for them to be rigged and skinned so that we could eyeball the defamation and general shapes. So I moved over to creating some of the new hair and beard styles as they aren’t effected by skinning. Trying to get a better spread of shape variety than the ones we currently have in game. The textures aren’t final as we are planning to bake a bunch of these down onto one texture atlas.


We plan to have modifiable weapons, with a variety of attachments. So to test this we will use a pretty stock standard MP5 and give it a couple of scopes, stocks, silencer, and clip sizes. If this all works they way we want it to, we will go about adding a bunch more, both stock weapons and ones with more of a Hurtworld feel 😉



I’m in modding-town this week. You may have seen a new item appear on the Workshop in the past few days. It’s my little test mod for the upcoming expansion of the SDK! The Shigi Statue. Not a high-quality mod by any means, as that model is some real programmer art, but it does look pretty neat in a base!


All the ground-work is laid, and architecture built as far as I can tell. Probably still some kinks to iron out, but at this point you can make a bunch of construction attachments in the SDK, export them out as a package, upload them to Steam, and then just by putting a line in your server’s autoexec, it’s in and working! You can only add items to the Construction Hammer at this point, although we’ll be able to do items soon when ItemV2 goes live.

So how will this all look to a mod maker who wants to create their own set of pieces? Well, I’ll be making some documentation to explain in detail how everything fits together. You won’t have to do any coding or anything like that, and for the most part I think you’ll be able to find an existing piece in the default set that is similar to what you’re making and just adjust the configuration slightly. You’ll be able to use your own models, textures, and materials all native to Unity, or use our existing assets (which will make your mod super duper small and quick to download!). A server can also choose to not load the default construction pack if they want! So you’ll be able to do mods that completely replace the default set!

And how will it look to players? Well, you’ll just join a server as usual, and it will download whatever mods it needs. And you should be good to go! Workshop handles all downloading and updating. Good on ya, Valve.

There’s currently a few limitations that I want to try and get rid of before we go live, like the ability to define your own construction attachment point types in a mod. But we’re most of the way there. As always – I can’t wait to see what the community does with these tools. And I can’t wait to extend them even further!



Some good progress on ItemV2 this week. I’ve been punching on with the Unity animator system to allow me to drive our equipment animations explicitly while still letting Unity’s Mechanim drive things like walking jumping etc.

There are some cool APIs called Playables that are almost usable, but do to the fact that additive blending (layering animations over eachother nicely) are missing we are restricted to a few nasty hacks. Specifically the hard part is doing smooth transitions between equipment animations while explicitly setting the position in an animation we are each frame. The reason we need to drive the animation position each frame is to give us the ability to do things like attach a magazine mod to a weapon that gives 20% faster reloading. Trying to propagate that the speed of the reload animation needs to be increased, and by how much to ensure it doesn’t get out of sync with our simulation state machine is very tricky. What we do instead, is tell the animator each frame:

Set animation player to “Assault Rifle Reload”
Set animation position to 30% of the animation
Render Frame
Set animation player to “Assault Rifle Reload”
Set animation position to 31% of the animation
Render Frame

This works like a dream, and allows the state machine to drive the animations without double handling and leaving places for the animations to get out of sync. The problem comes in when we try to cancel the reload. We want to smoothly interpolate back to the idle position or to another animation. There is a Crossfade method we can call, however as soon as we tell the animator next frame where we want it to be, it trashes the Crossfade snapping to the new animation which looks like balls.

To workaround this, we were forced to drive the speed of state on the Equip layer by a generated parameter, and only explicitly tell the Animator where to be when it isn’t where we want it. If everything is working correctly, we set the speed of an animation before playing it, and call Crossfade whenever we want a change and allow it to play out. If we detect it has drifted from our own State Machine simulation, we force it back into place and let it keep going solo.

This is working like a dream now. What this means for us, is that we no longer need to think about how equipment animates. We build our equip state machine that controls the logic and don’t need to double handle anything. We can also now modify on the fly, any duration or speed property of any state in our simulation by parameters like Attack Speed, Reload Speed, Fire Rate, Draw Speed, Bad Melee hit recovery etc without worrying that synchronizing our animator is going to be a nightmare. As these properties are liquid, we will be generating random bonus values when procedurally generating items, rarely will you see 2 items that are created equal!

Once again, all these systems are completely modifiable as Equip is mostly state machine configuration which writes out to JSON.

Here is a complete state machine for the melee weapons in action in all its client side predicted, perfectly deterministic, arbitrary configuration driven glory:


‘Keep your City Beautiful’ Is not my motto.

I’ve been throwing garbage all over the place, trashing the city. I made some sets of boards that litter the streets, these help break up the road texture. I’m using geometry currently, which may change to a decal system in future, where texture is applied to create a similar effect.

When building the city I use a system of making geometry then fitting the geo into a part of the texture sheet that looks good. This means we save on texture memory and load times. The only downside is that we don’t make as many unique textured objects. The upside is we don’t end up like GTA V and have a billion year load screen and better performance. This is important, because we have a lot of players running some lower end machines.

StreetLevelDecor_0006_Layer 2 StreetLevelDecor_0007_Layer 1

I have added some fenced off areas with sea containers to reflect perhaps a quarantine/walking dead/martial law type vibe. This will give players some cover when moving up or across streets and helps fill the streets and break up the playspace.

StreetLevelDecor_0000_Layer 8

I’ve changed the bottom floors to a two storey internal lobby situation. The shopfronts have changed to reflect that also. I will probably make a couple more general shopfronts to mix this up a bit.

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StreetLevelDecor_0004_Layer 4



This week I’ve been diving deeper into our equipment system working on integrating baking into our code base. With Spencer’s help we’ve been working on a new skinned mesh data format that will give us both a nice format for sharing custom gear through asset bundles (that can then be shared through Steam workshop) as well as allowing us to spread out the baking process over several frames to eliminate any frame rate spikes.

The plan is to distribute our base character model with the SDK allowing anyone to create their own equipment and then skin it to our characters skeleton so it will deform properly under animation. Once this step is completed there will be an importing step as part of Shigi Tools that will convert the mesh into our new format as well as run all the preprocessing we can to speed up the bake.

Generally when meshes are created they only store references to the bones that deform them (i.e. a character’s shoes don’t need to know anything about the arm bones).
Whilst this is efficient memory wise it creates a problem when baking as the final mesh needs to know about the entire skeleton, which requires joining the bone lists together and then updating the bone weight references to ensure they still point to the correct bone in the new list.

Another potential problem is when 2 equipment pieces are created and share the same bone (ie. the hats and the masks share the head and neck bones) but don’t share the same space (i.e. The hat might have its origin at the neck and a mask might have its origin at the nose). When this occurs you get conflicting data about the bind-pose for the bone (and this is what was releasing the kraken last week). The bind-pose represents the position of the bone in the skeleton when the mesh was skinned to it (relative to the meshes local space) and is used to transform the mesh into the proper position under animation. In the shot below you can see that the head model and the hair model have a different origin and orientation, you can also see the bind-pose for the neck bone according to both meshes, because bones to bindposes have a 1:1 relation per mesh we need to make these the same values. To solve this we have to transform all the meshes into a shared space (the characters root usually makes the most sense).
Luckily all this processing doesn’t have to be done at real-time if we push it into an import step when creating the asset.


It’s still going to be a little while until this stuff shows up in game as it’s being integrated into the larger overhaul of the item system that Spencer has been working on.
We’ve still got testing and things to work out with the best way to handle customization and random variations but we are really excited to see what you guys will come up with.


Hurtworld Update #33


So this week we tested out culling methods for all the trash and objects that we will be adding to the street level. We had planned on using groups of objects placed and repeated around the city at first. The idea is that Unity will batch objects that are the same and therefore use less resources.

In the image below the yellow blobs indicate object groups that would be visible to the player within a specified radius.


After doing some further testing it turns out that placing objects individually then using a grid culling system is actually more efficient. This version (which I’m very glad won out) allows me greater control with placing objects. I can get more unique scenarios if I am not restricted to predefined object groupings.

In the second image below the shaded in yellow grid spaces show all objects within that grid space that would be visible to the player. This version is the more efficient.


And some images of a few more items that I managed to create after going through the object cull testing.



Hi everyone, I’m Tom, the new developer at Bankroll. My first week has been mostly been getting setup and trying to get up to speed with the codebase.
I’ve been working with Mils on our environment workflow, creating tools to bake mesh objects together intelligently saving on both memory and draw calls. We can also bake groups of objects into clusters given just a custom cluster size, this provides a nice workflow to setup LOD and culling groups. So far we’ve seen good results from baking lots of detail objects as well as larger modular building pieces. Once these tools mature a bit internally you should see them pop up in the MapSDK for everyone to use.
I’ve also been prototyping baking skinned (animated) meshes together at runtime to speed up our equipment system as well as being able to load and re-target imported meshes to our skeleton at runtime. At the moment I’ve got bugs that look like the kraken has been released (see below) but hopefully this will eventually serve as the beginnings of a system to allow you to share custom equipment through the Steam Workshop.


This week I’ve been working on a couple more optimizations, fixes for exploits and bugfixes. Large servers should load a bit quicker, and the issue of players getting disconnected for high ping when joining a large server should now be resolved. We also plugged up another exploit that could be used to create rock bases, which are a really sucky thing as they do give a player or group pretty much raid immunity. We should be pushing out a patch, within the next 24 hours, depending on how testing goes. This patch will contain lots of little fixes, some mentioned above, as well as double loot crate spawn speed in Diemensland, which should make towns a bit more viable for farming runs.  Multiple terrains should now also be supported, which some community maps have been limited by up to now.


I’ve also started on creating an architecture for mods and extensions to Hurtworld. I’ve talked about this before, with extending the construction system to allow for community made construction pieces. Players will be able to make furniture, new walls, new material types, new attachments, new decorations, you name it! We’re pretty excited for this. What’s required first though is a system to manage the mods. Luckily, Steam Workshop and Unity do a lot of the heavy lifting for us, and will make this architecture (hopefully) much more painless than it would be otherwise.

When you connect to a server, the server will share a list of dependencies, a list of mods that it needs to download from the Steam Workshop. This is done right now with community maps. Then, your game will download all the required mods (or just find them if they are already downloaded and up to date), load them into the game, and you’ll be good to go! While this sounds simple, it does require a bit of a rework as to when things are loaded and unloaded into memory. Currently, construction attachments are initialised and cached when the game starts. We’ll need to move this initialisation step into when you join a level, and make sure we’re properly unloading the assets when you disconnect. Otherwise, joining servers with different mods enabled consecutively is going to result in some pretty broken and weird behaviours!

We’ll be putting all these tools into the SDK (do we need to get rid of the “map” bit now and just call it the Hurtworld SDK?). Just as we did with the maps, we’ll give out all the current construction attachments in the SDK as well, so you can pull them apart and see how their made before you make your own. I’m really pumped to see what the community does with these tools!


More character stuff for me this week 😉 I foresee I will be doing character work for a while as we have quite a few ideas that we wish to implement and test. Before jumping straight into creating the new gear, modelling the high poly, retopologizing, baking out maps etc, I have been knocking up rough approximations of some of the forms we may wish to use. This gives us a way to eyeball shapes and silhouettes and figure out if they are a direction that we wish to head, and hopefully raise any issues we might stumble upon down the road and lower the amount of reworking of assets.

Troublesome areas tend to be where sets of things intersect ie: the waist or neck are. I generally need to make sure that pieces play nice with each other and hopefully avoid any traits that we dont find appealing like soggy hips that can make it almost look as if the character is wearing a nappy.



Here are a few more character concepts showing mechanical/engineering type gear and some random facial pieces.


There is also a sheet showing a sort of early game light armoured ranger type set and a more heavily armoured set.



Most of this week has been working away on the Item system. As I am deep in code land, there isn’t much high level stuff that would interest non technical people. Instead I will go into a bit of detail about the internal workings of the Item restructure. Beware: Here be dragons.

The existing item system used a hierarchy structure, where a base object defines behavior that all is descendants require. For example a weapon item needs a list of effects, a mesh attachment to the player, some simulation logic for equipping etc. Then each more specific version of weapons like Automatic Gun or Hatchet require less boilerplate code to implement.

This works to a point, but as most systems in games, the hierarchy gets so large that items end up with an array of functionality that they don’t actually require because some ancestors required it (kinda like humans with an appendix).

As in the near future we will be proceduraly generating items with vastly varying properties, visuals and behaviors, duplicating all of the data stored for a typical item would result in you running out of ram very quickly. Some servers get up to 50,000 item instances (1 stack = 1 item instance) after a couple of months of playtime. Currently as our items are static, these item instances simply refer to one of a few hundred item definitions that don’t change. Once we start pumping out completely new items and runtime, the item memory footprint will become exceedingly large. This leaves us with 3 simultaneous challenges:

  • 1. Support generating similar items without having to redefine common behavior (in both code and memory)
  • 2. Be simple enough to configure that we can move the definition to the mod sdk
  • 3. Support all future types of items we can imagine
  • 4. Not have any negative performance impact

To solve this I have been working on breaking the Item system from a hierarchy of inheritance to a composition model (similar to the structure of Unity itself).

In this model, the item object doesn’t have much information on it at all, instead it becomes a collection of simpler building blocks with limited knowledge of each other. This was very difficult before as the driving force behind equipment simulation was blocks of monolythic code that needed to be synchronized over the network. Since the restructure to let a configurable state machine drive the simulation and simply fire off events for more complex happenings, there need not be a central piece of code for the simulation of each item.

An example of building blocks to make up an item:
Static Mesh Attachment (Configured with a reference to the pickaxe model / material)
Item transitions (Turn to ash when temperature gets too high)
Effect builder (Configured with 15 player damage, and 15 mine damage)
Simple tooltip builder (Configured with name/description/reference to effect component)
Mine impact event handler (to receive events from the state machine when a mine raycast should be executed)

All of these components can be re-used across many different items and more can be added to produce any functionality that can be easily re-used, the configuration of which will be done inside the unity editor with a custom inspector I will create over the next few weeks. This should make things like new guns, player gear and other items trivial to create inside the SDK.

I have also been working on a concept to extend the vehicle skinning system to enable coloring of player gear pieces. We now have a technical proof for the system which will allow a schematic item dropped from a creature to have randomly generated colors on parts of it, and also allow dying your pieces to recolor them. I will probably handball this to Tom in a couple of weeks.

If you are wondering why I am spending so much time on rebuilding the Item system when I am working on Infamy, this is a required building block for the changes we intend to make. Significant changes needed to be made to items, so while here is probably the best time I will get to improve the foundations in all areas needed to support future plans. This makes changes take longer in the short term, but will start paying dividends in a couple of months.

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