Surface data fuction

physenv.AddSurfaceData( string properties )
I know I have to add a surface data function because when I drive my car and break the server crashes. How do I use the new surface data function and where is the new location because I know in gmod 12 it was scripts/surfaceproperties/ and I know it has changed since then.

Sorry for bumping, but I feel as this needs a response since I haven’t found any helpful documentation on it. Here’s a quote from the GMod wiki:

So I thought it would be pretty simple, and it turns out it is. Here’s what I found in the 1969 Dodge Charger addon

	"base"		"rubber"
	"friction"	"1.4"
	"elasticity"	"3"
	"density"	"500"

TL;DR: The string argument is basically a key from your old surface properties text file.