I'll add my way of doing this:
1. Define areas you want as contiguous in the UV map with hard edges (select border edges of the area, right-click, select
Hardness from the menu and then
Hard). Repeat until all areas are defined. I usually select the areas so that projecting them to flat surface distorts them (or the texture applied to them) as little as possible. .
2. Use Wings3D's own unwrapping - select all faces (tip: select the object in body selection mode and switch to faces selection mode), right-click, select
.UV Mapping., right-click, select
Continue and then
Projection Normal.
In the pic below you see an example at this stage, Asp Explorer from my
Z-ships OXP. Hard edges are orange, and the default helper texture is applied (the UV map is a mess at this stage).
Click on the pic to see it bigger
3. Rotate, scale, move & optionally combine the different parts of the UV map to utilize available space well and to get a coherent view of the model's surfaces. This part can be quite tedious if the model is complex and you have lots of areas surrounded by hard edges. In the pic below is again the same ship showing how I have rearranged the original UV map mess (seems to be the Police/Navy -variant).
Click on the pic to see it bigger
4. Save the UV map to disk, to serve as a base for texturing - deselect all faces/objects in the
UV Editor Window, right-click and select
Create Texture, select the newly created *ship*_auv (*ship* = name of the object you're UV mapping) in
Outliner and
Export. I usually make two of these, one with only border edges drawn and one with all edges drawn, and make these images with doubled dimensions compared to final texture size (2048x2048 for 1024x1024 texture). At least in earlier versions of Wings 3D (Windows XP), maybe even the latest stable-feeling (1.2), .png would result in a corrupt file, so other formats have to be used (.bmp seems to work fine, and because it is uncompressed, it doesn't introduce any artifacts). For some unknown reason these images tend to have holes in some edges (flood fill reveals these
), so plugging them helps a lot when you use these images in making the texture.
5. Proceed to make a great texture
.
To check your texture on the model, import it to Wings3D and apply it on the mesh:
File ->
Import Image... -> select the imported image in
Outliner -> right-click ->
Pick up Image -> select *ship*_auv in Outliner -> right-click ->
Drop picked object ->
Diffuse.
When you're satisfied, export the mesh as .obj and convert it to .dat. You can change all edges to Soft before exporting, but you can also define (up to 10? or 8? or 9?) Smooth Groups with hard edges, so your ship can have the Smooth attribute as true in Oolite and retain sharp bends where needed. For complex structures, you should use subentities along with hard edges/smooth groups.
Hope some of this helps someone
.