as ninjarat mentioned, take a peek at the surface functionality of iB3D for some examples of how to get at and manipulate mesh data.

the one thing i wanted to throw out for everyone (and you probably already saw it in my code) is that animated meshes in Irrlicht are not updatable.  only static meshes or SMesh based meshes can be altered.

'constants to distinguish between mesh buffer modes
Const MESHBUFFER_STANDARD=0
Const MESHBUFFER_LIGHTMAP=1
Const MESHBUFFER_TANGENTS=2

'this is an editable mesh container class.  it holds an irrlicht
'static SMesh and performs simple manipulations on it.  planning
'an animated mesh one too.  seperately or integrated, I have not
'yet decided.
Type TMeshContainer
    Field mesh:SMesh
    
    Function create:TMeshContainer(mesh:SMesh)
        irrmesh:TMeshContainer=New TMeshContainer
        irrmesh.mesh=mesh
        Return irrmesh
    End Function
    
    Method CreateSurface:TSurfaceContainer(buffermode=MESHBUFFER_STANDARD)
        surface:TSurfaceContainer=TSurfaceContainer.create(buffermode)
        mesh.addMeshBuffer surface.buffer
        Return surface
    End Method
    
    Method CountSurfaces()
        Return mesh.getMeshBufferCount()
    End Method
    
    Method GetSurface:TSurfaceContainer(index)
        surface:TSurfaceContainer=New TSurfaceContainer
        surface.buffer=SMeshBuffer(mesh.getMeshBuffer(index))
        Return surface
    End Method
    
    Method GetWidth()
        Return mesh.getBoundingBox().getExtent().getX()
    End Method
    
    Method GetHeight()
        Return mesh.getBoundingBox().getExtent().getY()
    End Method
    
    Method GetDepth()
        Return mesh.getBoundingBox().getExtent().getZ()
    End Method
    
    Method SetScale(sx#,sy#,sz#)
        TIrrContainer.IrrMeshManip.scaleMesh ..
         mesh,Vector3df.createFromVals(sx,sy,sz)
    End Method
    
    Method FlipNormals()
        TIrrContainer.IrrMeshManip.flipSurfaces mesh
    End Method
    
    Method Normalize()
        TIrrContainer.IrrMeshManip.recalculateNormals mesh
    End Method
End Type


'this is a container for a surface, which is simply a mesh vertex buffer
'and a format and access mode.  different formats are faster than others
'in specific operations but not others.  it depends on what you're doing
'what vertex format is best.  I'm partial to the standard format
Type TSurfaceContainer
    Field buffer:IMeshBuffer
    Field bufmode
    
    Function create:TSurfaceContainer(buffermode=MESHBUFFER_STANDARD)
        surface:TSurfaceContainer=New TSurfaceContainer
        surface.bufmode=buffermode
        Select buffermode
            Case MESHBUFFER_STANDARD  surface.buffer=SMeshBuffer.create()
            Case MESHBUFFER_LIGHTMAP  surface.buffer=SMeshBufferLightMap.create()
            Case MESHBUFFER_TANGENTS  surface.buffer=SMeshBufferTangents.create()
        End Select
    End Function
    
    Method AddVertex(x#,y#,z#,nx#=0,ny#=0,nz#=0,u#=0,v#=0,color:TColor=Null,alpha=255)
        If color=Null Then color=CreateColor(COLORTYPE_RGB,1,1,1)
        
        vert:S3DVertex=S3DVertex.createFromVals(x,y,z,nx,ny,nz,..
         _SCOLOR(alpha,..
         color.Red()*255,color.Green()*255,color.Blue()*255),u,v)
        
        buffer.getVertices().push_back vert
        Return CountVertices()-1
    End Method
    
    Method AddTriangle(v0:Short,v1:Short,v2:Short)
        indicies:Array_u16=buffer.getIndices()
        indicies.push_back v0
        indicies.push_back v1
        indicies.push_back v2
    End Method
    
    Method CountVertices()
        Return buffer.getVertexCount()
    End Method
    
    Method GetVertex:Vertex(index)
        Return Vertex(buffer.getVertices().elementAt(index))
    End Method
    
    Method SetVertexCoords(index,px#,py#,pz#)
        vert:Vertex=GetVertex(index)
        vert.setPos Vector3df.createFromVals(px,py,pz)
    End Method
    
    Method SetVertexNormal(index,nx#,ny#,nz#)
        vert:Vertex=GetVertex(index)
        vert.setNormal Vector3df.createFromVals(nx,ny,nz)
    End Method
    
    Method SetSurfaceColor(color:TColor=Null,alpha=255)
        If color=Null Then color=CreateColor(COLORTYPE_RGB,1,1,1)
        For index=0 To CountVertices()-1
            vert:Vertex=GetVertex(index)
            vert.SetColor _SCOLOR(alpha,..
             color.Red()*255,color.Green()*255,color.Blue()*255)
        Next
    End Method
    
    Method SetVertexColor(index,color:TColor=Null,alpha=255)
        If color=Null Then color=CreateColor(COLORTYPE_RGB,1,1,1)
        
        vert:Vertex=GetVertex(index)
        vert.SetColor _SCOLOR(alpha,..
         color.Red()*255,color.Green()*255,color.Blue()*255)
    End Method
    
    Method SetVertexTextureCoords(index,u#,v#)
        vert:Vertex=GetVertex(index)
        vert.setTCoords(Vector2df.createFromVals(u,v))
    End Method
    
    Method GetVertexColor:TColor(index)
        vertcolor:SColor=GetVertex(index).GetColor()
        Return CreateColor(COLORTYPE_RGB,..
         Float(vertcolor.getRed())/255#,..
         Float(vertcolor.getGreen())/255#,..
         Float(vertcolor.getBlue())/255#)
    End Method
    
    Method GetVertexAlpha#(index)
        Return GetVertex(index).GetColor().GetAlpha()
    End Method
    
    Method GetVertexPosX#(index)
        Return GetVertex(index).getPos().getX()
    End Method
    
    Method GetVertexPosY#(index)
        Return GetVertex(index).getPos().getY()
    End Method
    
    Method GetVertexPosZ#(index)
        Return GetVertex(index).getPos().getZ()
    End Method
    
    Method GetVertexNormX#(index)
        Return GetVertex(index).getNormal().getX()
    End Method
    
    Method GetVertexNormY#(index)
        Return GetVertex(index).getNormal().getY()
    End Method
    
    Method GetVertexNormZ#(index)
        Return GetVertex(index).getNormal().getZ()
    End Method
    
    Method GetVertexTexU#(index)
        Return GetVertex(index).getTCoords().getX()
    End Method
    
    Method GetVertexTexV#(index)
        Return GetVertex(index).getTCoords().getY()
    End Method
End Type