I was creating a Direct3D/DirectX 8 "Terrain Rendering Function" which loops through every vertex and renders it into Direct3D.. but this takes too long to loop through and I would much rather have it do them all at the same time.

First, I attempted to use two class modules:

The first, labeled (PreTerrains) had a function that would use RaiseEvent to an event labeled "TerrainRendering".
[code]Event TerrainRendering()

Public Sub StartRendering()
RaiseEvent TerrainRendering
End Sub[/code]

The second class, labeled (Terrains) was 'withevents' declared to the first. (Sorry, hard to word it out):
[code]Dim WithEvents clTR As PreTerrains

Public Sub clTR_TerrainRendering()
    Msgbox "Test"
End Sub[/code]

On the main form, I had a couple copies of the second class declared to ensure there were isntances of them able to catch the raisevent call.
[code]Option Explicit
Public cllTR(5) As Terrains
Public cmTR As PreTerrains

Private Sub Form_Load()
Dim intC%
For intC = 0 to 5
Set cllTR(intC) = New Terrains
Next intC

Set cmTR = New PreTerrains
cmTR.StartRendering
End Sub[/code]

The problem is, whenever I tried it, nothing would happen. (I never received a messagebox.)

Any help would be appreciated., or, if you can, explain another way to do multiple copies of a function/functions at once.

Unless you have multiple processors or hyperthreading, you are unlikely to see a speed improvement from running those functions at the same time. And the problem with your code would seem to be not assigning anything to cllTR(intC).clTR (and not calling that).