Alternate UV Map for the Aircraft Skin Technical Details

The progress of my work in this month will be relatively slow, because I still have some additional activities linked to my “daily” job. Nevertheless, it is going on.

The original texture map (UV map) finished in the previous post (Figure 63‑1) is appropriate for the color textures (camouflage, national insignia and other markings). In this mapping various parts of the airplane overlap each other, so the pattern of the test image remains continuous:

Figure 63-1 The basic texture mapping – for the camouflage and other “color” textures (UVMap)

While such an arrangement makes the camouflage painting easier, it would be impossible to use such a map with overlapping elements for another important texture: the image of the aircraft skin details. In this post I will shortly describe, how I prepared an alternate UV map for this purpose.

I am going to recreate all the panel seams, rivets, and hatches that you can see in the reference drawings using a height (bump) texture. The final effect will look as good (or even better) as with the details modeled “in the mesh”, while drawing these elements in 2D is much simpler and requires less work than the modeling in 3D. What’s more, I will use this image as the base for other important textures (reflection texture, transparency texture).

I prepared for this texture an alternate UV map (Figure 63‑2):

Figure 63-2 Alternate texture mapping – for the bump map of the technical details (UVTech)

To get decent results even in the close-ups of the final model, I need for the texture of the technical details a high resolution image. The simplest way is to enlarge the image, but it consumes the computer memory and increases the rendering time. To make better use of the available image space, I “packed” all the airplane elements more tightly. I also used another trick: because the left and right side of this airplane differ only in a few relatively small areas, I decided to map here only the left side of this model. I will use the same map for the right side. Later I will map the few faces from the right side that contains the differences in the empty fragment of this image.

To determine new size and locations of all model parts on this new map, I copied in Inkscape the UVMap layer (see previous post) with all its sublayers. I named this alternate map UVTech. I played for a while with the wings and main part of the fuselage. Ultimately I decided that I have to enlarge their size by uniform coefficient: 130%. The same coefficient applies to all other model parts. (The most important thing is to keep all these elements in the same “scale”. Otherwise you would have on the final texture rivets of different sizes, and other, similar errors). Then I moved and rotated some of the model elements, fitting them into the available space. In this way I created the first approximation of the new alternate UV map:

Figure 63-3 First approximation of the alternate UV Map (Inkscape)

Using fragments of the scale plans, I also prepared an alternate reference picture that matches this layout (you can find it in the Blender file, linked at the end of this post). I used both of these pictures in creating this UV map in Blender.

To create an alternate map (named “UVTech”) in Blender, I had to repeat following steps for every mapped mesh in the model:

1. Copy the existing UVMap into new map, and rename it to UVTech:

   

   Figure 63-4 Creating a copy of the first UV map (Mesh Properties pane)

2. Resize the mesh faces on this new map by 130% (I typed the exact value of “1.3” using the keyboard input feature):

   

   Figure 63-5 Resizing the mesh faces

3. Place the enlarged mesh faces as in the reference drawing:

   

   Figure 63-6 Fitting the faces to the reference drawing

 Sometimes during this process I introduced small improvements: for example, I decided that I can shrink the areas on the control surfaces leading edges. (They do not contain any details, and are obscured by the wing or the stabilizers). It allowed me to fit these elements into the reference drawing (Figure 63‑7):

Figure 63-7 Fitting the control surfaces

When this work was over, I replaced the contents of the UVTech layer in Inkscape with the final shape of the UVTech map. (I exported it from Blender as an SVG file, as I did in the previous post).

In this source *.blend file you can evaluate yourself the current version of the model, and here is the Inkscape file.

In next week I will start to draw the image of the technical details of the aircraft skin.