Also, try using a bit of LUA
-> Documents -> Unique CRE without ASM
Because I decided I did not want to use this method of multi-CRE as I wanted the space back, I thought I would share this with people, itís very simple and gives the perfect illusion of multi-CRE, but it takes up a chunk of space in the area GFX, so only use this method if you got plenty of room in all your area GFX.
First thing to do is get your door GFX sorted into a neat pile at the bottom of your area GFX, like below.
After this is done, reimport the GFX into Smile and go to the graphics editor, from there, replace all the door GFX, and any other CRE GFX you want to change with the tiles, in the CRE tiletable, after a while, you will have all the doors done.
And that is pretty much it, I worked it out while I was working with Kraid's GFX, anyway as usual credit is very much appreciated as I was not going to say this until Return To SR:388 was finished but I felt kind, and stuff, so make sure to credit etc etc.