there are different possibilities:
1. Use terrainy at your current position and the position you would have on the next frame (x,z) and use that to calculate the steepness -> fastest most likely
2. make it pickable, do a vertical line pick and use PickedNY. the smaller it is, the steeper the surface is.
1. Use terrainy at your current position and the position you would have on the next frame (x,z) and use that to calculate the steepness -> fastest most likely
2. make it pickable, do a vertical line pick and use PickedNY. the smaller it is, the steeper the surface is.