# Angles of a normalized vector

I’ve been messing around with vectors and angle a lot and have hit a mental roadblock.
I’m trying to make a SENT that hovers a little bit above the ground (and moves like a vehicle, but first things first). The problem is that it will over at the wrong angles. I need it’s pitch and roll to match the slant of the surface it’s hovering over.

Here’s my trace code:
[lua]
// Trace down from the outter bounding radius
local startTraceDown = ( self.Entity:GetPos() + self:OBBCenter() ) + ( self.Entity:GetVelocity():Angle():Forward() * self:BoundingRadius() )
local endTraceDown = startTraceDown + Vector(0,0,-1000)
self.traceGroundNorm = util.QuickTrace( startTraceDown, endTraceDown, { self, ply } ) – Trace the ground
[/lua]

I tried using the Angle function and RotateAroundAxis, but to no avail. How would I get the pitch/roll angles to match the ground below a SENT?

HitNormal will be perpendicular to the surface the trace hit. You want it to be parallel? What’s wrong with rotating it?

[lua]local angle = trace.HitNormal:Angle( );
angle:RotateAroundAxis( angle:Right( ), -90 );[/lua]

The roll is already correct, you don’t need to rotate it.

Oh. I thought I remembered reading somewhere that the roll gets taken out with some of these functions. I can’t remember which one though.

-snip-

So will it do the roll for me?

Try it.

``````

entities/object_machine/init.lua:101: attempt to call method 'Angle' (a nil value)

``````

[lua]
function ENT:Think()
// Trace down from the outter bounding radius, starting at the front of it’s current move vector
local startTraceDown = ( self.Entity:GetPos() + self:OBBCenter() ) + ( self.Entity:GetVelocity():Angle():Forward() * self:BoundingRadius() )
local endTraceDown = startTraceDown + Vector(0,0,-1000)
self.traceGroundNorm = util.QuickTrace( startTraceDown, endTraceDown, { self, ply } ) – Trace the ground
if self.traceGroundNorm.Hit then
self.baseAngle = self.traceGroundNorm:Angle()
self.baseAngle:RotateAroundAxis(self.baseAngle:Right(), -90) --This gets our pitch and roll to be parallel to the surface
else
self.baseAngle = self:GetAngles()
self.baseAngle.pitch = 0
self.baseAngle.roll = 0
end
end[/lua]
Line 101 is line 7 here.

You are calling Angle() on the traceres table, You should be calling it on the HitNormal of the trace.

[lua]self.BaseAngle = self.traceGroundNorm.HitNormal:Angle()[/lua]

You’re right. Silly me.

util.QuickTrace results a TraceResult structure and not an angle.

Edit: Damn :ninja: