Align to Normal and look down slope...

Unity Engine
1

Hi all,

I kinda got stuck on this and I feel there might be a nice way to do it.
I’m trying to align to the surface normal but also have the x axis always oriented to look down the slope of the surface it’s on.

Is there an easy way to do that?
Thanks,
Pete

2

Not sure how you are going to get the “look down slope” vector, but when you do you can use vector3.cross to “combine” with what you currently have. Will be a “look right of slope” vector when using vector3.cross though.

An alternative is using a series of rays (3 of them should do) to get the downward facing vect that way instead, although it would be more expensive.

What’s this for anyway?

3

Here’s a trick that might help you: when the y axis vector isn’t 0,||1||,0 the normalized vector2 of the x and z components is roughly the direction towards the “down” slope.

Vector3 yAxis = transform.up;
Vector3 xAxis = new Vector3(1f, 0f, 0f);
if (Mathf.Abs(yAxis.y) < 0.999f)
{
Vector3 towardsDown = new Vector3(yAxis.x, 0f, yAxis.z);
xAxis = Vector3.Cross(Vector3.Cross(yAxis, towardsDown), yAxis).normalized();
}

I might have the order of the components of cross mixed up as a warning, which might give you the vector going “up”, so you might have to move them around.

1 Like
4

Hey guys thanks for that.
I wanted to use something like this to potentially orient my character to the facing downhill based on where they were standing. I’m still just prototyping really so things are a little loose and I’m not sure if it’s going to work.
P.