[Deora11]

I have a problem which is driving me nuts, cause it should work, but refuses to do so.

I have been converting a ship in Blender, which has its Detail0, and multiple layers parented by said detail (turrets, separate subsystems, etc). Each model has its own UV texture, making up 1 LOD and 5 children, each with their own UV (6 in total). Upon exporting the whole scene to a Collada dae. file, then loading into PCS2, one program kicked the bucket and half my UVs are missing, with the rest making a messy texture for all the models. Example: instead of Model 1 with UV 1 and Model 2 with UV 2; UV 1 ceases to exist and UV 2 is used for both Models 1 and 2.

Save exporting and UV texturing each model individually (which screws my AO bake), is their any way to fix this problem. Maybe I've made a rookie mistake somewhere (considering I am one), and a veteran knows the fix? Or is it one program being incompetent?

This problem is preventing my 'advancement' with 2 models, and I'll be glad to see it solved.

[zookeeper]

I don't know Blender nor how anything related to exporting from it works, but just in case this has any relevance: PCS2 and the pof format don't support multiple UV channels. They can of course have multiple textures per model/submodel, but that doesn't really have anything to do with the actual UV's of those models/submodels.

As said, I don't know anything about the Blender->PCS2 pipeline so this might be completely irrelevant, but I suppose there's a chance it might give you ideas for alternative setups to try.

[Deora11]

But doesn't the GTD Erebus and Titan use multiple UV mapped textures? Battlestar Sobek as well?

I thought any non-tiled ship used uv mapping for greater quality and diversity. How would you perform a similar texturing style otherwise?

[DahBlount]

No ship in FSO uses multiple UV maps,. For example, the Erebus uses a single UV map with multiple textures and certain faces assigned to certain textures, and if you were to open up the Erebus in Blender and look at the UV map of the detail0 object without aliasing for texture assignment, it would look nonsensical and absolutely disgusting with overlapping UVs everywhere. However, if you were to select all the faces assigned to a single texture, you'd find a clean UV map.

[Deora11]

So instead of selecting each individual object and unwrapping them, a have to select all objects and unwrap just the once? Eg. Select Detail0 and all its children, hit space and smart UV project.

[DahBlount]

No, each object technically has its own UV map, however copies of the same object will have effectively the same UV map.
You seem to have some misconceptions about UV maps and how they work. If you hop onto the #freespace IRC channel tomorrow between 11AM and 5PM US MST, I can give you a better rundown of how UV maps work in Blender and FSO.

[Deora11]

A UV map is a 2d texture projected on a 3d object, like unfolding a cube into 6 square faces, I know what a UV map is. As I'm 'trying' to explain, my detail0 has its BC304-main texture with its AO bake. A subobject, say the antennas, has its own BC304-antenna texture. Since they are different objects, they have different UV maps.

However, as an example, in PCS2, whilst both objects are present, the BC304-main texture is NOT in the textures column and the BC304-antenna texture is spread across both objects. Examples of said situation are attached.

How it looks in blender with its AO baked textures...



What PCS2 does to it.....

[z64555]

Sorry to interrupt, but a UV map is not a texture, but rather a set of normalized coordinates (U and V) associated with the vertices and polygons of the 3D object it is mapping. "Map" here, is not like a paper map you use to navigate the city roads, but is a mathematical term to mean a function or algorithm that transforms one set of data into another set of data. For example, the function U = mX + b maps values of X into values of U. the coordinates you are setting in the UV map are like the b, and the size of the texture that'll be used is like the m (it's a little bit more involved, but that's the general idea).

Regarding to your pressing issue, it looks like it might be a UV channel issue, or your texture might not have been loaded by PCS2 to begin with. UV maps are separated into "channels" on a model, if you have the wrong channel applied to the object's polys, then the thing will look garbled. Hopefully DahBlount can help you a bit more there as he has more experience with Blender.

[Deora11]

Using what knowledge gained from everyones help, I've narrowed my problem down to the multiple materials used for each model, due to the conversion process starting from a sketchup build. I deleted all materials except the ones shown in the UV/Image Editor as the Active UV Maps, and voila 



SHE LIVES!!!

Now, to turret and create damaged subsystem models. Or perhaps proceed with the Hesperides now I 'think' I know what I'm doing. All part of the learning process. 

[Scooby_Doo]

There's another little gotcha I didn't know about till just recently... flipped uvw maps.  They don't seem to show up in freespace, or at least I haven't noticed they're behavior but they exist.