So I got a new model for my mod, its too good that its bad :/ IDK why it deforms like shit I've heard people said that the more polygons on your model, the better it deforms. Well, that is not the case here.
It may deform badly because the physics model (Nodes and Beams) don't line up well with the graphical model. You may have some parts of your model connected to the wrong nodes from the physics model. Vehicles that come with the game tend to use way less polygons than that, I presume the devs have some good reasons for that beyond optimisation.
I think it's the same way it was in ror. When the model gets deformed when the structure deforms, it heavily relies on a well optimised mesh because the deformation from the n/b will "bend" the edges if you know what I mean.
You can use the decimate modifier but it will mess up the topology. --- Post updated --- The best solution would be to retopoligize the mesh or model it from scratch but that's a lot of work.
Sadly since the model is triangulized you lose all control over the edge loops pretty much and you can't easily optimize it. Luckily you might be able to salvage with using the tris to quads function to clean it up since the faces appear to be criss crossed. I can't garantuee that tho. But when you get a nice quad topology you can either select edge loops and press X > delete edge loop. or like littleturdlet said you can unsubdivide it either with the un-subdivide function or the decimate modifier. Also, you probably need to unsubdivide it if you want people without a beast of a computer to run this mod. Because that's way too high poly for a smooth game model.
press a to select all, go click delete, and find 'Limited Dissolve' then press ctrl+t to re-triangulate it this will likely screw up your polyflow, but theres nothing you can really do about it id just recommend finding a new model