trace.HitPos returns nil

[Mossman1223]

Been trying to get an entity to spawn at the position the player is looking at, but within a certain distance. Found some code that should work... but it doesn't.
This is in init.lua of my gamemode.
[lua]
function BuyHealthKit( ply )
if ply:Team() == TEAM_SUPPLIER then
local healthkit = ents.Create( "large_medkit" )
healthkit:Spawn()
healthkit:SetPos( Hit )
healthkit:Activate()
else
ply:PrintMessage( HUD_PRINTTALK, "You must be a supplier to buy supplies!" )
end

local trace = {}
trace.start = ply:GetShootPos()
trace.endpos = trace.start + ply:GetAimVector() * 85
trace.filter = ply

local tr = util.TraceLine(trace)
local Hit = tr.HitPos
end

function BuyM4( ply )
if ply:Team() == TEAM_SUPPLIER then
local M4 = ents.Create( "wep_m4" )
M4:Spawn()
M4:SetPos( tr.HitPos )
M4:Activate()
else
ply:PrintMessage( HUD_PRINTTALK, "You must be a supplier to buy supplies!" )
end

local trace = {}
trace.start = ply:GetShootPos()
trace.endpos = trace.start + ply:GetAimVector() * 85
trace.filter = ply

local tr = util.TraceLine(trace)
local Hit = tr.HitPos
end
[/lua]

When I try to spawn the M4 I get the error

Expedition/gamemode/init.lua:246: attempt to index global 'tr' (a nil value)

And when I spawn the Healthkit I get the error

Expedition/gamemode/init.lua:227: bad argument #1 to 'SetPos' (Vector expected, got nil)

This should be working, I looked at some code from the wiki and some other gamemodes, and I don't see whats wrong with it. When I used
[lua]
local tr = ply:GetEyeTrace
entity:SetPos( tr.HitPos )
[/lua]
It worked fine, but spawned the ent at the place you were looking at even if it was on the other side of the map.

[Kogitsune]

You're doing it wrong.

It should be:

...
tr = util.TraceLine( trace )
local Hit = tr.HitPos
...
M4:SetPos( Hit )
M4:Spawn( )

When you're calling it, Hit was nil since you haven't traced yet.

[Mossman1223]

So your saying I need to out the code for the trace before the actaul SetPos?

[Kogitsune]

Yes

[Mossman1223]

Worked like a charm, thank you very much.