I'm not sure what the brush model is. Most games use either a point system where there's only one contact point with the road or a soft body simulation like PC2, which is actually very detailed and includes water routing for wet weather racing. Suppose that could be a brush? ACC I think has moved from a single point system to a multi-point system, so they have an inside, center, and outside point, which contributes to my questioning the lack of a centerline on Beam's tires. The ACC guy said the old single point method caused issues with kerbing as it suddenly changed angles, but maybe beam slightly mitigates that by already having an inside and outside. --- Post updated --- "Fixed." It's an ongoing process and the road surface now essentially acts like a sponge and the tires clip through it slightly. On the older tire models you could visually see the impact of jumps and lower tire pressure because they physically interacted with the surface, now they clip through it. I guess it's not a huge problem in favor of better physics, but the visual aspect especially for rock crawling which they seem very focused on is now worse. I was going to explain how the current model works, but got distracted. Currently, the tire model doesn't do thermals nor wear and the way flats work is very bizarre. They said before they wanted to do thermals properly, with a contained volume of air in the tires that heats up... which... is a neat idea, I have no clue how feasible that is. It seems like thermals and wear could be done on a per-node basis, and then they could even simulate flat spots that will lead to punctures. They've got to be calculating how much friction the nodes have, seems like higher values should lead to higher temps and more wear. For flats, I'd rather instead of deleting nodes which looks bizarre and causes confusion it just went to 0psi like... real life. Maybe there's a technical reason why they don't.