TIS are actually switching to a 3D type system to make the walls in the game to actually reduce drawing time and such (and drastically reduce memory too). They've already done this with the character models back in 2012 (wow, that long ago now). See here for recent developments: http://projectzomboid.com/blog/2013/09/iso-revolution/ and back for the character decisions:http://projectzomboid.com/blog/2012/05/on-the-reanimated-dead/
Although for a smaller project 2D, hand drawn is great (usually better looking IMO). Some other forumers can probably give some good advice.
You have, essentially, two options: draw all your characters yourself, or render them from 3D software. The first way is the most straight-forward but time consuming depending on how many frames of animations / characters you want. The second way faster for pumping out a lot of animations (assuming you're familiar with 3D software) but complicated if you're striving for good quality at low resolutions.
If you're going to draw the characters yourself - and any pixel art animation software would suffice - Pro Motion, for example (http://www.cosmigo.com/promotion/index.php) - there are a couple of things to consider:
A character in isometric perspective really ought to be a little top-down (like in pic A, below).
However, for simplicity of drawing and animating, you can get away with it being side / front on (like in pic B. It's less ideal, but because in isometric, vertical walls stay vertical it doesn't stand out too badly and makes animating a hell of a lot easier.
As far as walls and floors go... your basic isometric shape should be something nice and neat - the diagonals should be across 2 pixels, by 1 up/down:
Walls in isometric are extremely straight-forward. You can draw the wall as if it were a flat texture, and then just shift every two pixels across up one, and that will then shear the texture into isometric:
As a 3d Program I can highly suggest blender. It is free and there is nothing that can't be done with it: http://www.blender.org/ Just as an example ... this is a low poly model I have made ages ago using blender.
Once the modding tools are out I hope it will be easy to expand the game models with clothes etc. @Binky: How many polygones do the vanilla models have before you "pixelate" them?
DaChucksta reacted to Ontogenesis in Isometric Graphics