I'm not sure how you you'd do it in photoshop since I would guess rotating a seamless tile would destroy the seam and doing it tileable in diamond shape first would really be a pain but perhaps another avenue is to use Direct3D to do you're tiles. That's what I moved to and its not too bad to learn. You can do seemless square tiles and then simply create a camera angle gives an isometric view. You other items on top (trees, rocks, whatever) do not necessarily have to be 3d. A good example of this type of engine is Ultima Online. Not only is it not too bad to do but it leaves you open to more interesting 3d possibilities, slopes in you're terrian, effects, and so forth.

What do you use for World, View and Projection matrices? I've recently been experimenting with different values (I just moved over to using LVERTEX rather than TLVERTEX with just 2D values). It looks okay with a regular "look-down" type setup, but the perspective can lead to some interesting/odd sprite artefacts.

I've had a look on the internet for
tutorials regarding this but I have been
unsuccessful. I want to make the
joins between tiles seemless. Does
anyone know how to do this or
know of a link? I primarily want to
do this using photoshop.

Ta

I just started learning IM very recently so the transforms are not totally behaving for me either. I'd be curious to see what others are doing transform wise on this subject. Any input folks?