If you’ve done the last two exercises, this one will make sense. If you haven’t – go back and do ‘em!

Think of multi-tile objects as single tile objects that are squished up against each other. That is, what makes a multi-tile object different to a single is that at least one edge needs to match the end of another tile. Sounds hard? Nope!

If we have the A-buffers greyed all around the edges then there’s going to be a gap between the tiles. If we have the edge where they touch in white then there won’t be any gap.

So that’s what we do for multi-tiles. We get rid of the gap by making the edge white. Easy!

Step 1: In your A-sprite select your object (generally by selecting all the black and then inverting the selection).

Step 2: Get a brush with a white colour and run it down the edge where the tiles will meet. Bingo! No gap

   Here's an Example - These are the A-Sprites for the Mondrian Painting from the Original Sims (That's the 2-tile painting of a black and white photo)

If you have a look at the 2 A-Sprites of the Mondrian painting you can see the straight edge that they share and the 3 dots and 3 holes are not alias-ed.

OK - Here's another Example.

I've made a round table, and letting T-mog generate my medium and far zones, I get this effect.

 As you can see - there are dots through the middle - this is where the A-buffers are telling the object that's is partially transparent.
This is why - if I select the black ground with the mask tool [M] - we can see that there is a some seriously dark bits in the middle.

To fix it, all we need to brush the common borders with white. (Notice, we leave the grey stuff alone for the bits where the table doesn't touch the other tiles. After all - we want it to be a circular table - not a hexagonal-whatsit one!

Just like that!

Import it back into T-mog and Voila!

 No funny dots in the middle. (Of course you will need to do it for each and every piece in the medium and far zooms to fix the whole problem. But once you get the hang of it, it doesn't take too long.

Which reminds me - I've got some older objects that I need to fix  for this!

OK - so go try it for yourself!