Grouping texture maps and adding semi-transparencies to the final texture map
Many of us use, when building a 3D object, several textures for their objects.
It is a very good habit, it is faster and very efficient, especially if there are transparencies and if we use the "Merge" function that allows to insert sub-objects already finalized in your object, for example the wheels of a vehicle. It is also more efficient to split its object into several pieces in order to master the "UV mapping" of each part of the object. The result if you do not group the texture maps is a "cx" file with several materials and several texture maps after exporting to "3ds" and converting to "cx" with "Object Converter".
This method is very effective when the UV mapping of the subassemblies is already performed correctly, with well-aligned edges, good scales for each element of the pattern.
This method of buildings 3D object, reliable and timeless, works correctly with the version 1.XX of Condor, and it is important, as much as possible, to keep it.
But, as written by OXO, version 2 of Condor will no longer admit this possibility. For isolated objects ("cx" file), only one material and only one texture map will be accepted.
If you have semi-transparencies, such as glider canopies or shadows, you will need to use "tga" or "dds" texture map files. In this case, a new constraint concerns the type of file "tga" for the textures which must imperatively be of type 2 or 10.
Photoshop does it well and it is almost perfect with Gimp.
All these new constraints seem to come from the use of DirectX 11.
However, we had to be organized to group all the textures into one and get a single material and texture map.
Grouping the textures in a single one will in most cases require to increase the size of the texture, and move, for example, from 512 x 512 pixels to 1024 x 1024 pixels, or else to decrease the resolution, to increase or differentiate only certain parts of the elements of the pattern. It is a delicate choice. But, as you can always reduce your texture map in your cx file, work with a bigger files (4096 x 4096 pixels).
To help you to choose, here's what to keep in mind:
If you double the texture from 512 to 1024, you can group 4 textures of 512, without any reduction in resolution, but if you have more textures you can have 9 places in your square with a resolution decrease of 100 to 66%, that is a reduction of 33%.
These are the patterns you should adopt, knowing that when you rearrange your pattern elements, in the "AutoUV" window, you will get a gain in the area and you will be able to add other elements.
To be concrete, you all know the static ASK 21 that is in the Patagonia scenery.
This version 4 had 9 textures, and with 2 pilots and 1 shadow, there were 22 different textures, but they could be modulated in size and used on several liveries for other gliders. From another point of view, this object was composed of 15 objects and had 8530 faces, 13707 edges and 5241 vertices without shadow.
This model had a major fault at the junction between the 2 parts of the fuselage, although acceptable in Condor V1.X. This first problem had to be corrected imperatively as well as minor details.
The second problem was the pilots, coming from the green pilot of Condor. He had 3439 triangulated faces, 5219 edges and 1794 vertices. Compared to the glider alone with its 1288 faces, it was absolutely necessary to find a solution, in order to reduce the weight of the final file cx which was 645 kb in its lightest version.
The third problem is that, being subjected to a single texture, it had to be usable by several versions of the model in various positions. This implies, in addition to the 2 pilots, the presence of a third person to hold the end of the wing. From this universal model, it could, while keeping the same texture, be declined in multiple versions, namely:
Ground ready to take off, with 2 pilots and a third character, plus shadow (this is the basic version).
Then in flight, with 1 or 2 pilots, without shadow, at different altitudes and attitudes of flight.
Finally, on the ground, so with the shadow, the glider tilted on the right or left side, with 0, 1 or 2 pilots, cockpits open or closed, but this is already a classic in Patagonia.
The little green pilot was to be considered obsolete, and for that we had to find an appropriate and with a standard pose answer, we tried to simplify it. After several, more or less, successful versions, we have created a half-androgynous character (neither boy nor girl, but easily transformable) who, after a "mirror" transformation, becomes an accomplished pilot or a secondary character of only 974 triangulated faces, 1475 edges and 503 vertices that are declined and accessorized at our convenience and, of course, with a single texture.
If it is the first time you have to group textures on a complex object, we recommend that you work on a copy of your object. Copy that you will renew under a different name for each major step of the process, unless you use the "Save Incrementally" option of Wings 3D.
Once, the basic pieces created, they must be assembled by a succession of "Merge" to obtain the basic model with its multiple textures. Then make the necessary corrections and complements. Finishing can be carried out later.
Before beginning the assembly of the texture maps by successive combinations, it is necessary to remake the "UV Mapping" of each part with the final dimension of the texture and to have previously chosen a location in the final map so that when the elements of the textures will be gathered together, they do not overlap. Provide between each element of the pattern (Isles) a distance of 4 pixels and 2 pixels for the edges of the texture map.
To remake the "UV Mapping" of each part, there are two possibilities, after possibly partial grouping of elements by a "Combine", according to the method described below.
If your texture map is badly made, select the part concerned and make a complete new "UV Mapping" or at least partial "UV Mapping" in keeping the "edges mark for cut", as explained in the previous subjects.
Before creating the texture of the part concerned, you have to scale, group the elements of the pattern and move them to the right place.
If your texture map is correct or requires some little adaptation, select the relevant object and then from the menu: "Window -> UV Editor Window", go directly to the final phase of "UV Mapping", the window "AutoUV", where you can make all the adaptations you like, then scale, group the elements of the pattern and move them to the right place.
Finally, create your texture in the final format chosen with preferably a final "Draw Edges" pass.
Last edited by Xavier
on Tue Apr 25, 2017 8:36 pm, edited 4 times in total.
*****- Xavier - (XDL * F-DELX) -*****