Visual Wear and tear texture mapping system design

I have made a crafting mini game in three js with various models of guns and their parts in which the users can craft guns from scratch combing the different parts of the model. All the parts are separate and none of them have parent child relationships. I am also using tweening and animations for each part. Each part has a health assigned to it which depreciates over time and can be reset. My question is how can i design a visual wear and tear system in which i can make ramdom variations of rust, scratches , dents etc. Combined and display them as an overlay on the different parts according to their current health. These need to cover the whole geometry of the different parts and need to blend smoothly with the default textures of the parts as they were exported from blender as glb. Any help would be appreciated

Lots of ways to approach that, but the simplest approach might be to .clone() the mesh, and replace the material of the clone, with some sort of noise based material or shader of a rusty/scuffed material… that you gradually cross fade to as the wear increases. You could use the .alphaRef value of the material to make the noisy alpha cut off at different depths… I have a really primitive example of something like that in this screenshot:

This one looks sort of like chipped paint if I had a shiny metal surface behind it, or imagine the pink part being a rusty texture, with shinier metal behind it…

Thank you for replying,
What would be the performance tradeoff for this method considering each weapon has around 10-13 parts? Is there a way to procedurally generate these textures of wear an tear without using external textures?

yeah. that should be possible. you can use noise functions, or a single separate noise texture to apply these kinds of effects. You can also modify the existing materials and augment them with the functionality via onBeforeCompile as well.

Thank you for your insights. Will try these methods to see which one works for me.