RimWorld Mods

Big and Small – Framework Mod

Author of the Big and Small – Framework Mod: RedMattis

Biotech Features Mod is a framework mostly for handling a variety of Biotech Features, such as genes of different sizes, as well as a variety of gene and graphics behavior, such as transformations, genes varying by body-type, and so on.

Big and Small – Framework Mod features

Bodytype Gene Graphics

Very simple usage, simply put “bp_” anywhere in the file path of any gene’s and it will force that graphic. If none match the pawn’s body-type, it will pick a random texture with “bp_default” in the file path. If there are none, it will just pick a random one, as per vanilla Rimworld.

Example usage:

  • BodyAttachments/LoS_SnakeTail/bp_default
  • BodyAttachments/LoS_SnakeTail/bp_fat
  • BodyAttachments/LoS_SnakeTail/bp_hulk
  • BodyAttachments/LoS_SnakeTail/bp_female
  • BodyAttachments/LoS_SnakeTail/bp_male

You can have multiple paths with the same tag, in which case it will randomly pick one.


You can swap the bodies of pawns using genes, this lets you e.g. create a terrifying pawn with 8 arms each with an eyeball in the palm.

The catch is that:
A) It requires Humanoid Alien Races setup for the body.
B) You need to swap to a specific body, you can’t mix half of one and half of another.

The Lamia/Naga mod has an example of performing a swap like this.

Facial Animation Gene Compatibility

Adds the ability to disable/enable Features from NL’s Facial animation mod via genes.

Big and Small

Pawn Size
This part of the framework adds methods for changing the size of creatures via StatDefs that can be applied from genes or pawn definitions such as HAR-races and applied a large number of effects to large/small creatures such as altered rendering size, health, damage, metabolism, self-production, etc.

The size changes are balanced to be in line with Vanilla Rimworld. The cosmetic size-scaling of sprites are non-linear, e.g., a human baseliner scaled to body size 10.0 would not render 10x larger.

The following size-related StatDefs are available:

  • Body Size Offset & Cosmetic Body Size Offset – Offsets the pawn’s body size in an additive way. The latter version is cosmetic only and won’t affect game mechanics. E.g., a body size 0.5 HAR race with a 0.6 offset would end up body size 1.1 and render roughly twice as large.
  • Body Size Multiplier – Just as above, but a multiplier instead. E.g., a x0.75 multiplier applied to a standard body size 4.0 Elephant would reduce its body size to 3.0
  • Head Size Multiplier – Increases or decreases the size of the character’s head. This can be preferable to just drawing the head texture larger for some gene-based heads since it will scale the headgear.

Other Big and Small/Better Prerequisites Features

For instructions on how to make infectious gene-based werewolves that change shape under the moon, check out the Discord linked at the bottom of this page.

Better Prerequisites

This framework adds a more robust system for prerequisites, hediffs, etc., than what Vanilla Rimworld offers for its genes.

The mod also lets you create genes and hediffs that disable genes. Hediffs can even disable genes that disable genes. You cannot have genes that disable genes that disable genes because of how it was written to avoid recursion.

The framework name comes from when it was just made for prerequisites, but the framework now includes hediffs that change a pawn’s genes, or spawn other hediffs. Vice versa for genes spawning hediffs.

For any Gene mod authors can specify any number of condition sets that must all be fulfilled for the gene to activate.

This being a framework it does nothing on its own.

Example of how it can look in-game:
Supreme Super Snek Ambush
Gene Prerequisites:

  • Any of: Snake Tail, Eel tail, Mermaid tail
  • Any of: Strong Melee, Feral Might
  • All of: Venomous Fangs, Coiled Jump
  • None of: Incapable of Violence, Weak Melee

Unlike the vanilla prerequisite system, genes with prerequisites from this mod can still spawn in genepacks or via random gene-generation.

Valid XML tags are: AnyOf, AllOf, NoneOf.

Other Random Stuff


  • AI normally won’t use combat-self-buff abilities. With this mod they will.
  • AI normally won’t use hostile abilities in melee range. With this mod they will.


  • Lets you apply damage that won’t randomly penetrate into people’s internal organs. (DamageWorker_Outer…)
  • Lets you have damage multipliers to more specific damage types (e.g. bullets, concussive, …)


  • Lets you make genes affect the size of raids as an alternative/addition to metabolism costs.
  • A whole bunch of other stuff. Feel free to use XML stuff from my other mods as inspiration. 🙂

Compatibility notes

Compatible with most mods. Safe to add to existing saves.

Feel free to make requests for features if there is something you’d like to see added to the framework.

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