Beta Road Grip Editor 1.31

If the mod isn't working for you, press CTRL + L (restarts Lua) and restart the map if you are already in one, which should make it work.

Road Grip Editor allows you to change the road surface grip in-game and in realtime, allowing you to simulate icy conditions, F1 levels of grip, and even negative grip on any map, without having to modify the values in the map or vehicle files! This is possible thanks to the current game code which allows you to dynamically update the road surfaces. And I am taking advantage of this to present you with this mod!



Version 1.31


Mod Showcase by WhyBeAre:



Tutorial on adding a UI app:
https://wiki.beamng.com/User_Interface_&_Apps

Usage (Version 1.31):

1. Select the Surface
The default surface is set to "All Surfaces" meaning that all surfaces will be modified. If you would like to modify an individual surface, click on the surface drop-down list and select from the many road surfaces, the one you would like to modify. Alternatively, you can select the surface the vehicle is on by clicking the "Get Surface" button.

Note:
Some surfaces such as "Asphalt" for example will also modify the surface grip of concrete and other "similar" surfaces. And some surfaces that you may think is a certain surface type may actually be a different type. For example, the surface you might think is of type "Asphalt" may actually be the "Asphalt Old" surface type, so you may need to do trial and error sometimes to find the right surface type.

2. Edit Parameter Values
Below the surface selector are the surface parameters which affect how the tires grip the surface. Next to each one is a question mark you can hover to get more information on them. And to the right of them are input boxes to modify their values. Hovering over the parameter's input box will tell you the minimum and maximum values that you can input. There are two ways to edit the surface parameter values:

• Right-click on the input box, delete the current value, and then type in a new value
• Use the up/down arrows in the input box to increment/decrement the current value

3. Apply Changes
Click on the "Apply Changes" button to apply the parameter values to the surface you selected.

4. Resetting Parameter Values
There are two ways to reset the parameter values for surfaces:

• "Reset to Default" will reset the current surface grip to default settings
• "Reset All to Default" will reset all the surfaces' grip to default settings

Note:
The applied settings will reset when you close out of the map.


Surface Parameters and Definitions:


The graph above gives you an idea of how tire friction depends on the slip ratio (the difference in velocity between the vehicle and the tire as a ratio). Zero or 0% slip ratio means that the vehicle's and tire's velocity are the same. And a slip ratio of 1.0 or 100% means that there is a two times difference in velocity between each other. Although, the game seems to use the difference in speed rather than a ratio between the tire and the ground, with having a "Stribeck Velocity" parameter.

• Static Friction (μ)
  • The type of friction that allows you to stop and is actually what the tires experience when they are not spinning out or locked up. This value is most of the time higher than sliding friction. In the graph, this type of friction is present in the zone between 0% slip and peak friction, and the tire is technically slipping.
  • Examples of static friction include:
    • Regular driving
    • Racetrack racing
      
    • Braking before wheels lockup
    • Accelerating before wheels spinout
• Sliding Friction (μ)
  • The type of friction that is experienced when your tires are spinning out or locked up as a result of going over the limits of static friction. And this is why ABS, Traction Control, and ESC exist to keep the car from experiencing sliding friction to give you the most grip. In the graph, this type of friction covers the zone to the right of peak friction. In the game, this is set as one value, which defines the lowest sliding friction value, and the distance and slope between peak friction and sliding friction are determined by the "Stribeck Velocity".
  • Examples of sliding friction include:
    • Drifting
    • Doing a burnout
    • Braking too hard and locking your wheels
• Stribeck Velocity (m/s)
  • This determines how quickly you transition from static friction to sliding friction when you go over the limits of static friction. This value determines the difference in speed between the tire and vehicle required to switch completely from static to sliding friction, and sets the steepness of the slope between static and sliding friction.
• Hydrodynamic Friction (μ)
  • The type of friction that is produced by the viscosity of the fluid (surface). This friction is proportional to the difference in velocity between the vehicle and the tires (e.g. the more you spin your tires, the more friction that is produced)
  • Examples of hydrodynamic friction include:
    • Spinning your tires in mud
• Roughness Coefficient
  • This value determines how well different types of tire treads grip the surface. For example, a value of zero works best for slick tires and a value of one works best for mud tires.
• Fluid Density (kg/m^3)
  • This is the density of the surface. If the density of an object is greater than the density of the surface, the object will sink, and if the other way around, the object will float.

• Flow Consistency Index (Pa*s^n)
  • This value is basically a coefficient used to scale the viscosity (η) of the fluid proportionally to the "shear rate" (basically the velocity of the object passing through the surface) to the power of the "flow behavior index".

• Flow Behavior Index (n)
  • This value defines the shape of the viscosity (η) vs. shear rate (γ) curve. And you can see in the graph and table what the curve will look like depending on the type of surface/fluid, based on this value. The game doesn't simulate Bingham plastics so ignore that.
• Drag Anisotropy
  • This value determines whether the object that rides on the surface will sink or float. Negative values cause the object to sink and positive values will cause floating.
• Default Depth (m)
  • This value defines the depth of the surface when the surface is flat and isn't overridden by the terrain.
• Skid Marks
  • I think this one is obvious enough?

Possible Future Features:

• Bug fixes of course

Troubleshooting:
If the mod isn't working for you, press CTRL + L (restarts Lua) and restart the map if you are already in one, which should make it work.