February 2017

RHS 0.4.2 Inventory Item Mass Revamp

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In the last patch, we made an improvement that not many might notice at first glance. In 0.4.2 we rebalanced the inventory item mass of all items, including weapons, magazines, grenades, missiles, rockets and explosives. This blog post will explain the reasoning behind this refurbishment as well as the method of it.

First, let me explain what this item mass is: In Arma, the “weight” of an item was not measured in pounds or kilos, but in so called “mass units”. They have no real-world counter-value, but are a mix of weight and volume. Those units are used for Arma’s stamina system and thus is directly connected to the player’s performance. According to the official wiki, the total mass a soldier can carry before being limited to slow walking is 1000 units (with the stamina system enabled).

01 – the „mass“ parameter in a magazine class config

Without anything on you or in your inventory, a soldier in Arma can sprint for about 60 seconds before being exhausted and limited to run normally. The turnaround is: The more you carry with you, the more unit points are stored in your inventory, and the same amount is also taken away from your Stamina.

02 – A standard loadout of an Arma3 NATO Rifleman. The inventory and stamina bar are half-filled.

03 – An over encumbered soldier. The Stamina and inventory weight bar are fully filled. The soldier can only walk slowly now.

How would you define the mass of a pistol? Would you say: mass = 10? That may be too high, or also too low (or rather, the item would be too heavy with a big volume or too light with a small volume)? Defining those values was always a bit of guesswork. This is why ACE3 community member commy2 came up with a simple formula to calculate the inventory mass units out of the real world weight. He takes the weight in grams, multiplies it by 2.2 and then divides this sum by 0.1. The result of this equation is the mix of volume and weight. This works great for most items, but it may result in issues with items that in real life have a low volume but high mass, like a mine for example. Hence we multiply the result with a SCALAR between 0 and 1, which helps us balance the issue (multiplying by 0.5 halves the final inventory mass). The second problem: Redoing every config entry for the mass of items is quite a task and requires some labor, but we got around to it: To simplify the process we created a Google Spreadsheet with all items, the real-world weight, the newly calculated inventory mass units and their old mass units.

As you can already see in this screenshot from our Spreadsheet, we adjusted some values with the Global Multiplier aka SCALAR to balance the final weight. Especially for the RPG-7 rockets we had to go down to nearly half their mass. Changes in this system did not only affect the item weight, but also the capacity of some vests and backpacks which had to be adjusted to the new standardized system. Some backpacks now have more space, some vests a little less, but most of them should retain the ability to carry a reasonable number of items. Furthermore, we had to adjust the inventories of some soldiers or even create new ones (like the USAF Javelin Missile Bearer).

To come to a conclusion: What does it mean for the normal player? Nothing, really. For you who simply plays with our mod the change nearly went by unnoticed. Some soldiers will have more stamina, some less, depending on their loadout. But for us, on the other hand, it means that we finally have a way to standardize one more config parameter that before was nearly impossible to get right. From now on we can keep the inventory mass of all items at the same level of fidelity, offering a much better experience when playing.


https://community.bistudio.com/wiki/Arma_3_Stamina https://forums.bistudio.com/topic/170411-how-to-get-the-players-current-inventory-weight/

Ps: As of today, (February 13) there is a bug with Arma’s calculation of magazines when in weapons. This might result in missile bearers being overloaded as the magazine mass is added twice to the full inventory mass amount.

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