As a blender user i've found exporting a material/colour ID map quite awkward, resorting to bakes and having to enable or disable blender options to get a clean unaltered diffuse colour render. A process that is both fiddly and time consuming.
By chance I came across the offical BLender uv layout addon to export the uv layout as a wireframe and noticed it had an option to export the diffuse colours. Sadly there was no option to only export the diffuse colours (i.e without wireframe), so I dug around in the python code I came up with my own version.
Blender Export Colour Layout Addon
- Download link
This is an addon for Blender that enables the exporting to png the unmodified diffuse colors of applied materials using the meshes uv map as a layout. In essence it generates a colour ID map for use in applications such as Quixel Suite DDO. As it does not use baking it is easier and quicker to generate colour ID map, it also (appears) to work the same regardless of whether you are using Blender Renderer or Blender Cycles.
It is heavily based on the original UV Layout addon and is still a work in progress, but it exports the colour map just fine. In the future I'd love to work out a method of assigning DDO colour link id's to Blender materials and export those, instead of having to set the materials diffuse colour.
The download has a brief read me with more details in it. If you have any problems with the addon feel free to post them in this thread and I'll see if there is anything I can do to help. I'm unsure if not going the baked approached means that something important is missing. As far as I can tell uv islands are not anti-aliased, but materials that share the same edges are and that appears to work fine within DDO.
Using Blender with DDO
Just a couple of notes about using Blender with DDO, specifically in regard to generating the required input maps.
After spending some time my advice would be not to bother trying to bake maps with Blender. There are some specific issues with Blender baking currently and it does not support some important input maps that DDO really needs for best functionality. In the end I've just found it easier to export your High poly, Low Poly and optional Cage mesh then use xNormal to generate the maps instead.
Exporting OBJ Format from Blender
The default settings seem to work fine, though do remember to enable 'export normals'.
It might be a good idea to enable 'triangulation', but i'd suggest it may be better to do that on the actual mesh to ensure consistency between exports.
My settings are to enable, Selection Only, Apply Modifiers, Include Edges, Write Normals, Include UV's, Write Materials, Objects as OBJ Objects. With Forward = -z forward and Up = y Up. Depending upon content you might find you need additional options enabled/disabled.
Problems with Blender Map Baking.
Currently Blender Renderer bakes object Space Normals using a different directional bias to that which DDO expects. This means front/back from Blender becomes top/down in DDO etc ( can't actually remember exactly which direction maps to which, just that it was wrong). This could probably be fixed with some messing around in Photoshop but its not worth the bother.
Blender Cycles Object Space Normal baking allows you to specify the directions assigned to colour channels, but sadly the baking process as of 2.71 is broken as the object is not baked in object space. From memory it doesn't reset the positional and rotation transforms or something.
Finally one of the most important input maps, Curvature is not directly supported by Blender and although DDO can generating one from other input maps, it will miss hard edges present in the geometry but that is not encoded into say the tangent normal map.
So just my opinion, but once you've exported the material colour ID map and the .obj versions of your meshes you are better off investing your time with xNormal.