RimRound - a Rimworld Weight Gain Mod

Howdy all! I was going to wait a bit before posting here but have decided to share a bit of what I’ve been working on earlier so that it’s not swept under the rug.

As the title suggests, I’m working on a Rimworld mod that adds a weight gain mechanic. However I intend for this mod to be rather large and comprehensive. The original thread where it was discussed is here:

To summarize the thread I’ll list what I’ve done and what I plan to implement.


  • Weight is measured and it's effects administered to pawn's through a Hediff that is applied at pawn generation.
    • The hediff currently affects movement speed, need for rest, need for food and manipulation (only at rather high stages)
  • When a pawn eats, a factor of the nutrition value of the food is applied as severity toward the hediff. (weight gain!) In the future, the plan is to rework this around the fullness and digestion system I'm working on (explained below)

  • Pawn appearance is changed dynamically depending on Hediff severity.
  • Custom bodytypes and weight levels is likewise not an issue.
  • To get around one of Rimworld's rendering limitations, I'm using the Humanoid Alien Races framework to adjust render settings. This allows for any size of pawn!
    • One of the benefits of using this framework is that it allows for many custom features as well as alien race support (with a simple patch). Custom heads, thought filters, apparel and trait restrictions as well as custom backstory assignments are all made easily with this framework. One more thing, which I know one person here is dying for is custom beds! Yes, this means blob colonists can become beds!
  • A complex system for managing pawn's diets allows for fine tuning and adjustment allowing for both weight gain AND weight loss. This is done through a new GUI element with dual sliders. It is currently in development, but mostly just in need of polishing.

  • This system uses the following features and terminology:
    • Hunger Thresholds – These are when the pawn seeks food. One and only one of these will determine this, but you must have one or the other. You can toggle between the two, as they serve different purposes. The targets are where pawns eat up to. Valid Threshold/Target combinations are Nutrition/Fullness, Fullness/Fullness and Nutrition/Nutrition.
    • NutritionHungerThreshold - This is similar to Vanilla. You pick a level that the pawn will seek nutrition. Vanilla Rimworld has this value set at 45% for humans. Setting this lower means that the pawn will only eat when they are more urgently hungry, and will eat until either the FullnessTarget or NutritionTarget.
    • FullnessHungerThreshold - This method is very different from vanilla. Pawns will seek food when their stomach reaches a certain capacity. This means a pawn’s nutrition should never be below full. If you choose this method you must use the FullnessTarget.
    • NutritionTarget - A pawn using the nutrition target will try to eat no more than this point. They will seek the appropriate amount of food to eat to reach this as closely as possible in one meal. In vanilla rimworld, this is 100%. By setting the nutrition target low, a pawn can lose weight.
    • FullnessTarget - A pawn will try to eat up to a certain fullness.
    • DigestionRate - When a pawn digests food, it adds to the nutrition stat as well as their weight. This rate determines that speed.
    • HungerRate - The pawn will always lose food at this rate.

  • Custom recipes for four larger meal types have been added to the appropriate workbenches.

  • The current weight limit goes up to 3000lbs. I know that's rather high, but think of it more as the hard ceiling that you can go toward but are unlikely to reach, and even then only with appropriate research and augments. Right now many of the debuffs around being large are centered on mobility. The movement debuff hits -100% at 840, but doesn't pass 120% until 1200lbs. This means that basic bionic implants to the legs could keep you mobile for a while beyond normal immobility.
    • Weight is expressed both in appearance and in the health tab. In addition, I've developed the ability to use the Mote system to display floating text in-game for future use with a scale.
    • The internal tracking of a pawn's mass is updated as well. This is what you see in the pod launchers and caravans as well as sometimes in their info tabs.
  • I've been researching how Rimworld's work code actually functions and it's quite elaborate but I finally understand it enough to add new work types.
    • Custom furniture including a feeding tube are in the works. I've made (albeit simple) custom graphics for it and learned how Rimworld's texture masking works.
    • A tentatively named feeding and feeder Jobs have been added and their functionality is currently under development.

The stuffing mechanic is as follows:

  • Hunger Threshold (Minimum allowable fullness)
    • When pawns reach this level they will try to eat until they reach target fullness.
    • The Hunger Threshold must always be less than Target Fullness.
  • Target Fullness
    • This is the amount that pawns will try to eat until, when they do. Once they fall below the Hunger Threshold, They will eat until they reach this point (or close to it).
    • Target Fullness can be above the Soft Limit, but never above the Hard Limit unless you want to kill them .
  • Soft Limit
    • The Soft Limit is when a pawn reaches what most would consider “full”. This can also be thought of as stomach capacity.
    • After this point, pawns earn varying levels of the stuffing hediff.
    • When above the Current Fullness is above the Soft Limit, the Soft Limit slowly will rise. This represents stomach stretching.
    • When Current Fullness is above the Soft Limit, pawns will get mood penalties or buffs depending on their attitude toward stuffing.
  • Hard Limit
    • Hard Limit is always x% more than Soft Limit. Naturally, then, the Hard Limit must always be above the Soft Limit.
    • Hard Limit is when the pawn dies or their stomach is ruptured due to overfilling.
    • Target Fullness should only ever be above Hard Limit if the goal is to kill the pawn.
  • Current Fullness
    • This represents the amount of fullness a pawn has. Generally, this should not be above the target fullness.
    • This value dictates what level of the stuffing hediff the pawn gets.

Features I Plan on adding:

  • Traits will be dynamically added as in the mod "Bad People". At the moment traits that make pawns sloppier when they eat, enjoy it more or tend to overeat come to mind.
  • Restricting when pawns can overeat based on colony abundance/scarcity of food.
  • Prisoner force feeding! Once the base feeder work types are finished this will be very easy.
  • New tech to assist in mobility and health for larger pawns.
  • I'd like to add overeating as a recreation activity certain pawns are allowed. The feeding tubes could be used for this.
  • Right now the only indication of a pawn's status is their health tab and (potentially) their appearance. Are there any other ways you'd like to see their weight expressed?

Features I would like to add eventually
These are things I do want to add, but will come after the initial release and are of relatively low priority.

  • Ideologies surrounding fat and weight gain + interactions with existing memes surrounding diet.

I wasn’t going to post outside of the thread, but I want to maintain awareness of my mod as well. I intend for this to be an ambitious and long term project but I am aware of the dangers of over ambition. With this in mind I intend to release it in parts/modules once the core-est features are done. Right now I need sprites, so if anyone is willing that’d be greatly appreciated. Otherwise I will eventually draw my own. I’m better at coding than I am at drawing however so it would take quite a bit of my time to do so.

Shortly I plan on launching a discord so that I can get more direct and swift feedback on ideas. Let me know what you guys think!

Here’s the link to the Discord!


NICE i saw you talking about this on my idea board thing glad to see you have made your own forum page for it


I have been waiting for someone to do something like this in forever, but I’m especially impressed with how you plan to handle dynamic sizes.

I don’t know if this is just personal preference speaking, but considering the wacky nature of how advanced archotech science can get (Ideology implies some archotechs or embodied theists are just modified humans that have become practically omnipotent) your upper weight limit still seems a little low. Take megaspiders for example- it’s an insect modified to be the size of a bear- 3,000lbs is only double the weight of the fattest people in the real world. I’m not saying we need pawns the size of the whole map (but I, for one would love that) but the nature of this mod allows for an extremely interesting potential colony goal. It’s okay if you’re “unlikely to reach” that goal, but even in my pre-ideology playthroughs I’ve had colonies that were completely untouchable, with several colonists in full archotech limbs and unbelievably impressive bedrooms. With Ideology’s age reversal technology, you could in theory have a colonist live forever. If you think going higher than 3,000 is a bit much, there’s an implant added in the Royalty DLC called the Armorskin gland, that modifies the skin of the patient to be highly resistant to bullets. Toss that in with a Tough trait, and they’re pretty much impervious to small arms fire. So technology to modify the body does exist in many forms outside of bionics. You could have 3,000 be the hard cap for baseline, unmodified humans, but perhaps an archotech techprint (for those really super advanced spacer tech research) is lying around in the world that has plans for a gland that increases the elasticity of the patient’s body, allowing them to reach higher weights than should normally be possible? It could be quite the expensive research. Maybe there could be stomach implants like the bionic stomach that help with metabolism and whatnot.

I’m not going to lie, I’ve been chomping at the bit for a mod like this. I’d honestly prefer if there wasn’t a hard cap at all, but I understand that it’s a lot of extra work for something that might not satisfy everyone. Maybe for the people like me that really, really want to overdo it, bare minimum could be a maximum visual size where the sprite stops updating but the weight and stats don’t, at least for a while. Immobility shouldn’t be an issue if the goal of the ideology is, for example, to make one of your pawns as fat as possible. Extra challenge comes from keeping them safe when they can’t move or defend themselves- but maybe they could still use psychic powers.

It seems like you’ve got this pretty much fleshed out (heh) and I’ll admit that I was a bit intimidated by Rimworld modding when I tried to do this myself, so I can’t thank you enough for this mod, honestly. I apologise if it seems like I’m coming off a bit ungrateful because the max size isn’t “big enough” for my tastes, but it’s always something you could set a limit for in the mod settings- maybe let players set the maximum weight themselves- there must be a few people out there that don’t want to micromanage the possibility of pawns going over their preferred weight, and people like myself that looked at the weight limit and thought “Well, how am I supposed to make a religion based around fatties if their leader can still fit inside buildings?”

One additional note, I’d like the option to turn off the Hard Limit on stuffing if possible. The idea of death via overeating is a pretty major turn-off (for me, I can’t speak for anyone else), and would no doubt kill the vibe intensely if I did it even by accident in a playthrough. That’s not to say you should remove it, especially because it opens up an interesting way to kill prisoners, and horrific war crimes are what Rimworld is all about.

You asked if there any other ways you’d like to see their weight expressed, outside of the health tab. I imagine it would have a kilogram indicator there, but one thing about the way Rimworld handles body sizes is that generally the larger the pawn (colonist, Thrumbo, etc.) the more food they require. I can’t begin to imagine how difficult a dynamic “body size” would be, but custom races like Ratkin and Nyaron have shown me that it IS possible to have a pawn have a smaller body size and require less food, although I don’t know if there’s evidence those two are fundamentally connected outside of the implication they are. It would be neat if weight was linked to body size and thus controlled how much food they required. I’m in love with the thought of needing several cooks working around the clock with the sole purpose of keeping one pawn satiated. And as that pawn’s size increases, they need more and more food just to keep their weight up.

Finally on the topic of traits I know some of them have dynamic severity. Masochist for example has qualifiers for minor, moderate, severe, and mind-shattering pain, which give intensifying levels of happiness based on their pain. Since weight would also be a Hediff and in the Health tab, it should be feasible to link a trait, (let’s call it Gainer as a hypothetical) to this weight and have the mood buff it provides from weight be linked directly to the severity of the pawn’s weight- +1 for a bit of chub, and depending on how far you really want to go, the maximum could be anywhere from +10 or even +40 (like from Catharsis.)

I want to be the first to play this mod when it releases. I’d love to help however I can (I’m not a coder nor a spriter, so I don’t think I can, unfortunately, I might be able to whip up a custom music theme for an ideology though, you know how they have that ambient-style music in the ideologies menu, like Techist? Something like that.)

Sorry, this post went on forever. I got a bit excited.


After thinking about it for a bit, I suppose I ought to elaborate. Given how I’ve defined the weight gain in the game using a hediff there isn’t inherently a limit - all it takes is adding a few lines in xml for additional severity levels, and stat changes. Weight updates continuously no matter what anyway. The only hard part would be adding those extra sprites. In my mind it was more of a goal for me to flesh out content up to that weight. I definitely wouldn’t rule out higher weights, they just may come later!

It is never something you can trigger by accident. Its designed so that in the off chance you did move the slider too far, it will pause the game and confirm that that’s really what you want to do. Pawns will never eat beyond their hard limit by themselves.

Already implemented! (though not through bodysize). Rimworld’s calculation for food need looks (roughly) like this:
lifestageHungerRate * raceHungerRate * hediffOffsetHungerRate * traitOffsets * a personal hungerRateMultiplier. (If a pawn is malnourished there’s more to consider). Bodysize does play a role in some things such as which predators hunt what AS WELL AS food maximum, but not directly hunger. I might look into altering bodysize depending on how useful that’d be.

( ͡° ͜ʖ ͡°)

That shouldn’t be difficult from my understanding of how traits work.
If you want to help brainstorm I could use trait ideas as well as things to make them trigger.
So far something like you said (we’ll call it feedee for now) could give buffs based on being big and debuffs for the inverse. I also had someone else’s suggestion of feeder, which would potentially give moodlets for cooking, maybe specifically the large meals. And, naturally, once the job system is done joy for feeding a pawn.

I really appreciate the enthusiasm! In the future I may take you up on your music offer. For now the ideology expansion is toward the bottom of the development list but it is definitely something I want to do.

so we should not rule out higher weights I think you ment to type wouldn’t rule out

Edited, thanks for noticing! I do that all the time.

it’s fine guilty of the same all the damn time

I am super hyped for this mod, I would love to be involved in a discord server of some sort so I can provide feedback and maybe even do some testing. As someone with some experience in game modding, I haven’t really seen a game mod start out this detailed before.

1 Like

My first post on this site after lurking for a while. This project seems very promising.
Whipped up some sprite edits, I volunteer to help get this project off the ground, pm me if you want to get in touch






These look great. Once this is able to download I will have to buy this game and give it a try.

as a side note, just as with the rjw mod, it would probably be best to keep the sprites optional for playability’s sake

another issue would be clothes for non-nudist pawns

1 Like

Those are incredible! I’ll definitely be getting in contact with you soon.

It’s one of my favorite games of all time. I definitely recommend it.

Do you mean for aesthetics or compatibility? Rimworld throws a fit if you try to put on clothes a body type that doesn’t have a texture for it but I believe this can be circumvented by assigning them all transparent images until real ones are available. With this approach they should still get all the benefits of the clothing just without the graphics. The other approach is to filter which clothes they can wear (you see this normally when you right click clothing and it says “x can’t wear this”). A combination of these approaches would allow it to be very stable. Mod compatibility would then be added through small patches.

However, disabling sprites on demand isn’t a bad idea. Yesterday I started using Hugslib for mod options so adding the option NOT to use the sprites should be easy.

I wonder it would be possible to have the weight skins override the graphic for clothing. so while my pawn is wearing that fancy marine armor I am more seeing the heavy weight they put on

Ok awesome never played this type of game before is it pretty difficult to get started or understand? I wouldn’t want to be overwhelmed and all. Also I saw this on stream and it has expansions when the mod is available will I need to get the expansions or will the base game work.

It is a bit difficult at first but no means the hardest out there. I recommend starting with Vanilla and no mods just to get the hang of it. No DLC will be required for most functionality but for a few specific things (particularly from ideology) some DLC might be required.

Alrighty perfect I will most likely pick it up when the mod is out so I can give it a shot. Sounds super fun.

I would add a mod setting to it to make it easier or harder at will


I signed back up (lost my old user account) and re-downloaded rimworld just to get ready!

Sounds like a super awesome project

Theres a vore mod getting started, Id love to see the interactions between this and that!