What's New in Rust's "Friday Devblog 17" Update

Friday Devblog 17 landed in late July 2014 and it's one of the densest weeks of the whole rebuild. Garry's own summary called it moving a huge distance closer to baseline, and the feature list backs that up - the furnace, sleeping bags, the torch, medkits and bandages, ironsights, fall damage and cold nights all went in, alongside a technically interesting replacement for traditional hitboxes.

Hitbox upgrades

The most interesting item is that Rust stopped using hitboxes. The traditional approach - as in TF2 - is to place simple boxes at the head, arms, legs and torso and trace against those, because testing against a character's thousands of triangles would be far too slow. It works well, but authoring hitboxes is manual work.

Instead, Rust uses a skinned mesh collider. Thanks to LODing there was already a very low-poly version of the player character, so that gets used for collision. Being a skinned mesh, each vertex is weighted to up to four bones. When the mesh is shot, the triangle ID gives the vertices, and the vertices identify the bone. Bones then carry attributes - the head and neck bones have damage multipliers so headshots do more damage.

Beyond simply being more accurate to the render mesh, the payoff is future flexibility. Adding a helmet, for instance, makes it easy to have a shot to the exposed face still kill - something possible with hitboxes but distinctly clumsy.

Survival items

The campfire was upgraded: it now heats you within a specific radius and burns you if you get too close. It also no longer allows spiralling towers of campfires, because you can't place a fire on a fire.

The furnace is in game and fully functional, turning ore into refined materials - though the devblog was candid that everyone on the team disliked the model and it would probably be replaced.

Sleeping bags are back and fully functional. Since this was about reaching baseline, the formula wasn't messed with, but extra groundwork went in for future expansion - named sleeping bags, or letting friends spawn in them, both called out as unexploited ideas.

The torch returned, so no more running around in the dark. Two things to note: you can hit things with it, though there are no animations for that yet, and you can extinguish and relight it with right mouse button.

Medkits, bandages and rad pills all work now - right click them in the inventory to use them. You can also drop anything in your inventory and it appears in a little sack as in legacy, with the eventual intention that most or all items get unique models, so a dropped piece of chicken looks like a piece of chicken.

Metabolism, damage and environment

The UI now shows notifications when you're too hot, too cold, hungry, thirsty, bleeding, poisoned, wet, or suffering radiation poisoning. Bill added a blood overlay so the screen gets bloodier the more injured you are. Fall damage from height was added.

Nights are cold again, so a fire is a necessity. Extra work went in here so that once the biomes are properly implemented they can each have different ambient temperatures. Clothing now carries attributes that update in the UI, though at this point they don't do anything yet.

Feel and viewmodels

Viewmodel sway was added, and the devblog's framing was that you don't realise its impact until it's missing. Ironsights returned on weapons where appropriate - positioning wasn't perfect but the technical work was done, and Garry was considering having the artists add more viewmodel detail specifically for ironsights. Sway and ironsights play well together.

A system for head and viewmodel shakes from taking damage, jumping, falling and shooting went in, with an admission that the first pass was probably overdone. On headbob, Garry had thought about it for a long time and concluded that most people hate it - the usual response being "make it so I can turn it off" - so he decided not to bother yet and see whether it's missed.

UI updates

Bill reworked several UI elements: the health bar disappears at full health, the new metabolism notifications sit top left, the crafting menu moved from the far left to the far right, and the main inventory UI is top-left aligned rather than centred. Garry flagged the last one as a change he wasn't sure about, while deferring to Bill as the design lead and inviting feedback.

AI progress

Andre got the bare bones of the AI system working, with wolves roaming the landscape. AI now has a field of view, a view distance and a listening distance, loses track of a target it hasn't seen for a while, and can switch to more threatening targets. The implementation uses behaviour trees this time around, which gives a far more visual, modular and debuggable structure than the previous approach.

Art and concepts

Bill built a waterfall, Goosey worked on stag and boar animations, and Dan wrapped up the sawblade tool before starting an improvised hammer.

Clothing concepts got serious attention, with an explicit design position: the team didn't want to reuse legacy's clothes, and wanted to avoid the obvious cliches - Mad Max and future-military being where everyone jumps first. Garry singled out Meg's hazard suit concept, noting the green welly boot is what makes it iconic, and that it tells a story - maybe the suit was torn up and the boot was what worked. Scott's headgear concepts drew praise for the skulls, boar head and metal bucket, on the grounds they're all things you could genuinely imagine wearing in a Rust situation. Paul added more weapon concepts exploring broken, mended and homemade weapons.

Closing

Everything above was one week's work. The two remaining fundamentals were the building system and the AI system, both important enough to justify taking the time to get right. The following week was earmarked for what Garry called empowerment - cleaning up, writing documentation and making systems artist-friendly, so new content could start flowing in.