# Pondus Inventory FI
\n*An addon for Sable that makes every block, item, and fluid pull its weight\u2014literally.*<\/p>\n
***<\/p>\n
> \u26a0\ufe0f **I warn you:** this mod is still under active development. To make it work with other mods, you will need to manually adjust the settings. You have been warned!<\/p>\n
***<\/p>\n
## What does it all mean? <\/p>\n
Pondus Inventory FI is a companion mod for the Sable physics engine. It provides you with an incredibly detailed system for determining how much blocks, items, **and fluids** actually weigh. <\/p>\n
Do you want to change the mass of a block or fluid on the fly using settings or in-game commands? You can. It also looks inside chests, barrels, fluid tanks, and any other containers and adds weight to whatever is holding them up\u2014so your airship suddenly becomes much heavier when the cargo hold is full of oil, or your portable water tank tips the scales when filled. <\/p>\n
Ideal for builds using **TerraFirmaCraft**, **Create**, **Sable**, or anything else where realistic mass, balance, and fluid dynamics are important.<\/p>\n
***<\/p>\n
## What can it do?<\/p>\n
### \u2696\ufe0f Mess with block & fluid mass any way you like
\nSet a custom base weight for almost any block **or fluid** using the config or the `\/pondus mass` command. You can even target entire groups with tags like `#minecraft:planks`, `#tfc:ores`, or `#forge:water`. And the config doesn’t just take numbers\u2014you can write simple math expressions right in the file.<\/p>\n
### \ud83d\udce6 Count the weight of everything inside containers
\nAny container (chest, barrel, Create’s moving contraption, fluid tank, you name it) automatically adds the total weight of all items **and fluids** stored inside. You can tweak an `inventory_multiplier` to balance things out (maybe only 80% of the contents count), and decide whether the container block’s own mass is included or not.<\/p>\n
### \ud83d\udca7 Fluid mass calculations (NEW!)
\nPondus now supports fluids via the NeoForge Fluid Handler capability. Define mass per bucket for any fluid, and the mod will automatically calculate the weight based on the actual amount in millibuckets (mB). Perfect for realistic water towers, fuel tanks, lava reservoirs, or chemical processing setups.<\/p>\n
### \u2699\ufe0f Configs that actually make sense
\nThere are separate config files for blocks (`blocks.json`), items (`items.json`), **and fluids (`fluids.json`)**, all using a clean JSON format. Expressions like `”base_mass”: “2.5 * stack_size”` or `”mass_per_bucket”: “0.8 + density_factor”` are fair game. And you can reload everything on the fly with `\/pondus reload`\u2014no server restart needed.<\/p>\n
***<\/p>\n
## Getting it set up<\/p>\n
### Requirements
\nYou need **Sable**. That’s it.
\n*(Fluid support requires mods\/blocks that implement NeoForge’s `IFluidHandler` capability)*<\/p>\n
### Config files
\nYou’ll find them in `config\/pondus_inventory_fi\/`.<\/p>\n
#### `blocks.json` \u2013 sets the rules for blocks. Example:
\n“`json
\n{
\n “minecraft:chest”: {
\n “block_id”: “minecraft:chest”,
\n “base_mass”: “2.5”,
\n “inventory_multiplier”: 0.8,
\n “include_container_mass”: true
\n },
\n “tfc:sand\/red”: {
\n “block_id”: “tfc:sand\/red”,
\n “base_mass”: “0.1”,
\n “inventory_multiplier”: 1.0,
\n “include_container_mass”: false
\n },
\n “#minecraft:planks”: {
\n “block_id”: “#minecraft:planks”,
\n “base_mass”: “0.5”,
\n “inventory_multiplier”: 1.0,
\n “include_container_mass”: false
\n }
\n}
\n“`<\/p>\n
#### `items.json` \u2013 item weights. Example:
\n“`json
\n{
\n “minecraft:iron_ingot”: {
\n “item_id”: “minecraft:iron_ingot”,
\n “mass”: “0.5”,
\n “per_stack”: true
\n },
\n “tfc:metal\/ingot\/cast_iron”: {
\n “item_id”: “tfc:metal\/ingot\/cast_iron”,
\n “mass”: “1.2”,
\n “per_stack”: true
\n }
\n}
\n“`<\/p>\n
#### `fluids.json` \u2013 fluid weights **(NEW!)**. Example:
\n“`json
\n{
\n “minecraft:water”: {
\n “fluid_id”: “minecraft:water”,
\n “mass_per_bucket”: “1.0”
\n },
\n “minecraft:lava”: {
\n “fluid_id”: “minecraft:lava”,
\n “mass_per_bucket”: “3.5”
\n },
\n “tfc:olive_oil”: {
\n “fluid_id”: “tfc:olive_oil”,
\n “mass_per_bucket”: “0.92”
\n },
\n “#forge:crude_oil”: {
\n “fluid_id”: “#forge:crude_oil”,
\n “mass_per_bucket”: “0.85”
\n }
\n}
\n“`<\/p>\n
#### Quick rundown of the parameters:
\n| Parameter | Description |
\n|———–|————-|
\n| `base_mass` \/ `mass` | A number or an expression (`”2.5″`, `”0.5 * stack_size”`, `”1.0 + nbt_power”`). |
\n| `mass_per_bucket` | Mass in kg for 1000 mB (1 bucket). Supports expressions. |
\n| `per_stack` | If `true`, the mass is multiplied by the number of items in the stack. |
\n| `inventory_multiplier` | Multiplier for the total weight of contents inside a container (e.g. `0.8` = 80%). |
\n| `include_container_mass` | Whether the container block’s own mass counts on top of its contents. |<\/p>\n
> \ud83d\udca1 **Fluid math note:** Mass is calculated as `mass_per_bucket \u00d7 (millibuckets \/ 1000.0)`. So 500 mB of water (`mass_per_bucket: 1.0`) weighs exactly 0.5 kg.<\/p>\n
***<\/p>\n
## In-game commands<\/p>\n
All commands need operator-level permissions (level 2). Here’s what you can do:<\/p>\n
| Command | What it does | Example | ***<\/p>\n ## For mod & pack developers<\/p>\n ### Register masses straight from code: \/\/ Register an item \/\/ Register a fluid (NEW!) \/\/ Register by tag ### Work with custom NBT data: \/\/ Writing ### Fluid mass calculation internals: \/\/ Expressions are supported too ### Runtime config changes: ***<\/p>\n ## Found a bug?<\/p>\n Great! (Well, not great, but you know what I mean.) Here’s what helps me the most: ***<\/p>\n > **License:** MIT. Use it, remix it, share it\u2014just keep the credit.<\/p>\n **Developer:** **CatCosYT** & **Fractal Interactive** The mod allows you to add the calculation of items in storage on ships to the Sable physics calculations.<\/p>\n","protected":false},"featured_media":123773,"template":"","meta":{"_minecraft_slug":"pondus-inventory","_minecraft_project_id":"jkDxc7XT","_minecraft_author":"CatCosYT","_minecraft_license":"MIT","_minecraft_downloads":185,"_minecraft_follows":9,"_minecraft_client_side":"required","_minecraft_server_side":"required","_minecraft_storage_type":"zip","_minecraft_archive_name":"pondus-inventory.zip","_minecraft_size_bytes":840392,"_minecraft_version_count":9,"_minecraft_updated_at":"2026-05-16T13:42:29.945259Z","_minecraft_date_created":"2026-05-04T04:41:55.524354Z","_minecraft_date_modified":"2026-05-11T18:09:04.862016Z","_minecraft_project_url":"https:\/\/modrinth.com\/mod\/pondus-inventory","_minecraft_icon_attachment_id":123773,"_minecraft_imported_at":"2026-06-07T06:39:10+00:00","_minecraft_import_hash":"d262391266d796d1c968e98a329666c2","_minecraft_versions":"","_minecraft_links":"","_minecraft_gallery":"","_minecraft_api_metadata":""},"mod_category":[89,873,126,158,91,92],"mod_loader":[160],"minecraft_version":[62,37],"class_list":["post-123772","mod","type-mod","status-publish","has-post-thumbnail","hentry","mod_category-game-mechanics","mod_category-library","mod_category-management","mod_category-neoforge","mod_category-storage","mod_category-utility","mod_loader-neoforge","minecraft_version-1-21","minecraft_version-1-21-1"],"yoast_head":"\n
\n|———|————–|———|
\n| `\/pondus mass
\n| `\/pondus mass
\n| `\/pondus mass
\n| `\/pondus mass
\n| `\/pondus reload` | Hot-reload all configs and clear caches | `\/pondus reload` |
\n| `\/pondus sync` | Rebuilds physics for all SubLevels (use after mass changes) | `\/pondus sync` |
\n| `\/pondus config showmass` | Shows the mass of items when hovering over them in the inventory | `\/pondus config showmass true` |
\n| `\/pondus config showblockmass` | Shows the mass of blocks when hovering over them in the inventory | `\/pondus config showblockmass true` |<\/p>\n
\n“`java
\n\/\/ Register a block
\nMassRegistry.registerBlock(“minecraft:stone”,
\n new BlockMassEntry(“minecraft:stone”, “3.0”, 1.0, true));<\/p>\n
\nMassRegistry.registerItem(“minecraft:diamond”,
\n new ItemMassEntry(“minecraft:diamond”, “0.3”, true));<\/p>\n
\nMassRegistry.registerFluid(“minecraft:water”,
\n new FluidMassEntry(“minecraft:water”, “1.0”));<\/p>\n
\nMassRegistry.registerBlock(“#minecraft:logs”,
\n new BlockMassEntry(“#minecraft:logs”, “0.8”, 1.0, false));
\n“`<\/p>\n
\n“`java
\n\/\/ Reading
\ndouble power = InventoryMassCalculator.getCustomDataValue(stack, “power”, 1.0);<\/p>\n
\nInventoryMassCalculator.setCustomDataValue(stack, “power”, 2.5);
\n“`<\/p>\n
\n“`java
\n\/\/ FluidMassEntry handles millibucket \u2192 kg conversion automatically
\nFluidMassEntry water = new FluidMassEntry(“minecraft:water”, “1.0”);
\ndouble massFor500mb = water.getMass(500); \/\/ Returns 0.5 kg<\/p>\n
\nFluidMassEntry oil = new FluidMassEntry(“tfc:olive_oil”, “0.92 * density_mod”);
\n“`<\/p>\n
\nIf you change configs at runtime, don’t forget to invalidate caches:
\n“`java
\nModConfig.CONFIG.reload();
\nInventoryMassCache.clear();
\n\/\/ Then run \/pondus sync on the server
\n“`<\/p>\n
\n1. Grab the log from `logs\/latest.log` and search for `pondus_inventory_fi`.
\n2. Tell me the mod version, Minecraft version, NeoForge version, and Sable version.
\n3. Describe exactly what you did, what you expected, and what happened instead. If there’s an error, paste the relevant part of the log.
\n4. **For fluid-related issues:** Include which fluid tank\/block you tested with and whether it implements `IFluidHandler`.<\/p>\n
\n**Discord:** https:\/\/discord.gg\/pZ42QYZTD6<\/p>\n","protected":false},"excerpt":{"rendered":"