SBD Dauntless, from scratch

If I were a BIG plastic model factory, I´d be already warming up my 3D printers and asking if you sell your model.

Wurger, Gnomey, Lucky13, VALENGO - thank you!
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In the previous post I promised that I will start the UV-unwrapping. However, last week I found a new edition of Bert Kinzey's "SBD Dauntless" book. After ten years break, Bert started to continue his "Detail & Scale" series, this time in a different form: digital editions. This e-book is the "updated and revised" version of an earlier publication (from 1995). For me, the most important part of Kinzey's books are the "walk around" photos. They differ from all other "walk arounds" by careful selection of the pictures and comprehensive comments that explain many technical details depicted on these images. Usually these comments are as important as the photos.



Take for example such a caption that you can find on page 102, below the picture of the forward firing guns (as in figure above):

All versions of the Dauntless had two fixed, forward-firing, .50-caliber machine guns which were fired by the pilot. This photograph was taken from the Pilot's Manual for the SBD-2, and it shows both of the two fixed guns in place. However, the manual also states that the left side gun was usually removed from the SBD-2 in order to save weight. This was done only on the SBD-2 and usually only during peacetime. Once the war started, the additional firepower of the second gun was more important than the weight advantage gained from deleting one of these guns.

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It is a great clarification that cites a reliable source: the original manual. In the other books on this subject you can find various, often contradictory versions about the SBD-1 and SBD-2 forward guns. For example:

Pilots' armament [of the SBD-2] was increased from one to two .50 caliber guns (Barret Tillman, "The Dauntless Dive Bomber of World War Two", Naval Institute Press, 2006, page 8);

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This statement implies that the SBD-1 had a single 0.50 gun! (And it does not tell us about the source of this revelation).

Another one:

To retain the center of gravity (CoG) position [in the SBD-2], one of the forward-firing machine guns was removed (Robert Pęczkowski, "Douglas SBD Dauntless", Mushroom Model Publications 2007, page 8);

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This statement implies that all SBD-2 had a single 0.50 gun because of the design reasons (aircraft balance). This is also an information without specified source.

You can find in the Web many other descriptions of the SBD-1 and SBD-2. I remember that I encountered somewhere yet another variation of this story. It stated that the pilot in the SBD-1 had two smaller, 0.30-caliber guns.

I am really happy that Bert gives us the ultimate answer on this issue. (In another place in his book he mentions that for this writing he used the six original manuals, one for every Dauntless version. That's why I take for granted his statement that all SBDs had two 0.50 forward guns).

In the chapter about wings (page 85) I found the confirmation of my hypothesis about the overlapped flap edges:



Compare figure above with the second-last picture from my post from previous week. This was a result of the deduction, because when I wrote it, I had no such a vertical photo of the wing with closed flaps.

However, when I studied the photos of the cockpit canopy, I noticed a difference in the shape of the rear segments:



Figure "a", above, shows a fragment of the photo, taken from above. It reveals that the upper part of the last segment had a cylindrical surface, and the radius of the cross section between the third and the last canopy segment was larger than in my model (shown in figure "b", above).

It was further confirmed by all other photos: the side edges of all cockpit canopy segments were parallel, while in my model they are not:



I had to be blind that I did not noticed this mistake before! In fact, it happens when you stick too much to your assumptions about particular shape. In such a state of mind you can see only the details that confirm your hypothesis, and neglecting the others. I assumed that the top radius of the subsequent canopy segments decreased like in the telescope tube: each segment has smaller radius than the previous one. In the effect I received much smaller radius at the end of the third canopy segment than you can see on the Detail & Scale photo.

As the first approximation of this radius I placed inside the model an auxiliary circle (Figure "a", below):



I fitted this circle between the sides of the previous segment and decreased it by an appropriate clearance. Then I checked how it looks in another reference photo (Figure "b", above). In this way I have found that it should be slightly smaller. Thus I started to search for the reason of such a result.

BTW: I used the same reference photo before, to verify the pervious cross section. I determined then that it had much smaller radius than the result presented above. This situation shows that you always have to double check every model element on multiple pictures!

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Finally I think that I found the reason: the canopy sides should have a little less steep slope in the rear view. The error comes from the wrong assumption about the shape of the pilot's canopy:



I assumed that the upper horizontal "sticks" of this canopy frame were nearly parallel to the fuselage centerline. In the effect the front and the rear edges of this segment were not parallel (figure "a", above). The photo from Detail & Scale book reveals that I was wrong (Figure "b", above). You can see on this shot from above that both horizontal elements of this canopy frame are parallel to the cockpit border edge. Thus I had to rotate a little the rear edge of the pilot's canopy, making it parallel to the front edge. It forced me to decrease (by scaling) the radius of the arc that closes the upper part of this canopy. In the effect, I will have to decrease the corresponding arcs in all subsequent canopy segments, including the last segment. As I mentioned in one of the previous posts, I tried to avoid such things, but nevertheless I am prepared: the meshes of my model are relatively simple, so such a modification is not a great problem.

If you want to create a precise copy of any complex object, be prepared that from time to time you have to step back and alter the shape of some finished elements. The work on such a model more resembles a "spiral" than the classic "waterfall" process.

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Well, I documented these small bur laborious modifications on the pictures below. Generally, in each canopy segment I had to rotate the side faces along their base (see it in the second segment, depicted in Figure "a", below). Then I scaled down (a little) the upper faces of such a mesh, decreasing in this way the cross-section radius of the resulting surface.



The third segment was more difficult, because the radius of the top arc in its cross sections increases toward the rear (Figure "b", above).

The most difficult part was the last, fourth canopy segment (see the picture below). First I formed its faces in the rotated position (figure "a", below), ensuring that it properly slides into the previous segment, and that its upper part forms a clean cylindrical surface:



Then I rotated it back into "closed" position, and verified all other details (figure "b", above). Fortunately, it seems that the radius of its rear edge did not significantly change, and it still fits the rear border of the cockpit. (It still looks like in the reference photos). The biggest change occurred in the frontal cross section of this canopy segment.

Indeed, I already altered this radius before: see this post, Figure 57-5. You can see that I made a wrong decision that time, decreasing this section instead of increasing the rear edge of the previous canopy segment. This is a typical "fitting" error, which occurs quite often!

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Figure "a", below, shows the modified shape of the cockpit canopy:



Figure "b", above, shows the same canopy with the updated frames. It is hard to notice any of my changes in this side view, isn't it? In fact, fitting anew the frame meshes to the altered canopy segments required even more time than the adjusting of the canopy basic shapes! I am really happy that some posts ago I managed to tame the temptation to recreate the internal frames of these canopies. Now I would have much more work with them.

That's why I am going to recreate all the internal details in the last, fourth phase of this project. In this way I am just creating "time buffer" for eventual new findings, like this one.

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Of course I checked the updated canopy on the reference photos. This time I did not want to be blind on eventual differences — as you saw in this post, even slight distance between the model and the photo can indicate a significant error. I slid all the canopy segments into "open" position, to compare them to the CAF photo (this photo has the highest available resolution - see figure "a", below):



To better see the model on this picture, I assigned a red material to these frame objects. As you can see, most of the canopy frames match the photo. However, there are two exceptions, on the pilot's cockpit canopy. The bottom ends of the middle and rear frames seem to be shifted (by about 0.2" and 0.3"). It could mean that the slope of these canopy sides had a slightly different angle. However, the front edge and the rear edge of this segment match the photo (figure "a", above). At this moment I will leave this difference unresolved — maybe in the future I will find something, which will help me to explain this difference.

There are also slight differences in the last canopy segment (figure "b", above). However, I think that I can explain them now. This part of the cockpit canopy has two degrees of freedom: you can slide it as well as rotate around its corner. The canopy in figure "b" seems to be rotated by about 0.5⁰. Such a small rotation can be within the tolerance of its lock mechanism. It can be caused by the gun doors, which seem to be slightly opened in this photo. There is also a thick rubber (or leather) strip around the rear edge of this canopy segment. It seals the rear border of the cockpit. (I will recreate it later). I think that the influence of the gun doors and this strip can rotate of this last canopy segment by such a small angle.

In this source *.blend file you can evaluate yourself the current version of the model, described in this post.

This post ends the "modeling" stage of this project. During this phase I formed the general shape of the model, and created all the surfaces which require the classic "image" textures. In the next post I will unwrap these surfaces in the UV space, preparing them for the "painting". For all other details that I will create during the last, "detailing" phase, I will use procedural textures, which do not require UV-mapping. (The only exception are certain elements of the cockpit interiors, like the instrument panels, but they will have their own, separate texture images).

Looking good so far!

Wurger, Gnomey - thank you!
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Because of the holiday break, during July and August I will report my progress every two weeks. I will return to weekly reporting in September.

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I have just begun the third stage of this project: "painting" the model. At this moment I am unwrapping its meshes in the UV space. I will deliver you a full post about this process next Sunday. Today I will just signalize how it looks like.

So I started by creating a new reference picture. It had to have a rectangular shape. Inside I placed my drawings of the fuselage, wings, and the tailplane:

The most important thing: all elements of this drawing have exactly the same scale. As you can see, I used flipped left side silhouette in place of the right side view. In fact, I should prepare a 2D drawing of the right side view first, then place it here. On the right side of the Dauntless fuselage, the steps to the gunner's and pilot's cockpits were located in different places. There was also a rectangular hatch of the luggage compartment. However, I am a little bit lazy, and I prefer recreating these details directly on the final textures. I will describe what I mean in August, when I report how I drew it.

I use the reference images to keep the proportions between all unwrapped model parts. Sometimes it is also useful for hiding the seams, as in the case of these wings:


I split the mesh into the upper and lower surfaces, and mapped it onto the corresponding parts of the reference drawings. On some textures (for example: the camouflage) it will be impossible to obtain an ideal continuation of the picture mapped along this seam. It is not a problem on the sharp edges, like the wing trailing edge. However, the rounded leading edge is a different case: I prefer to keep it "in one piece", hiding the texture seam in the first original panel seam on the lower surface of the wing.

When the mesh is mapped on the reference picture, I use another, standard test picture to ensure that the mapped image is not deformed


At this moment I have already unwrapped most of the model:


I still have to unwrap the engine cowling. When I finish it, I will publish a full post about this process, as well as the updated model. (I will do it on next Sunday — July 24th​).

In this guide you can find detailed step-by-step instructions how to map various aircraft model meshes onto texture images, as well as all other details of "painting" the digital models.

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Lovely work so far!

Wurger, Gnomey - thank you!

This week I finished mapping all the parts of my model onto a two-dimensional image. Figure below shows the test image, mapped on the model surface. (Its pattern helps me in keeping the same mapping "scale" for each object):


I did not "unwrap" the small details, like the parts of the propeller mechanism, because I will "paint" all the small parts using procedural textures.

Figure "a", below, shows how these meshes are distributed on the 2D UV map (you can see the reference image beneath). At this moment I mapped just a single (left) wing, the symmetric halves of the rudder and the fin, as well as the left side of the fuselage. The upper and lower part of the tailplane are symmetric, so I just mapped its left, upper side. I will create the other sides and symmetric elements later, at this moment I just reserved the necessary UV space for these objects.


In figure "b", above, you can see that the reference image looks like the first approximation of the skin details. In the next post I will draw an image of these details that fits these unwrapped meshes. It will be the base for all the textures I will create for this model.

In the rest of this post I will shortly describe my typical approach to UV mapping.

This post is not intended as a detailed step-by step guide. If you want such an introduction "for the absolute beginners", use this book. It is accompanied by many useful Blender add-ons, for example an add-on that exports all the unwrapped objects into such an SVG image, as shown in figure "a", above. (In the standard Blender you have to export each object separately).

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Let's analyze the wing case. I am going to map its upper and lower surface separately. Thus I defined two auxiliary vertex groups, to easily select these mesh parts:


I use the Project From View command to create initial mapping. For the upper wing surface I use the projection from the local top view of the wing object:


I shifted and scaled this shape, fitting it to the reference image. I used "pinned" vertices from the flat part of the wing surface to this image (using the Pin command). Then I invoked (in the UV/Image Editor window) the Unwrap command:


It "relaxes" (unwraps) all the faces that are not pinned. In this case Blender unwrapped the leading edge and wing tip edge.

I unwrapped the wing bottom surface I the same way. At this moment the seam line between the upper and lower wing surface lies in the middle of the leading edge (figure "a", below). While it is OK for the relatively sharp edge around the wing tip, the minimal discontinuity of the texture image on the most exposed, forward part of the wing would spoil this model. Thus I usually hide such a seam, leading it along the nearest panel seam line on the lower wing surface (figure "b", below):


When I marked the seam line, I called another Unwrap command. In response, Blender "teared" the bottom part of the leading edge from the lower wing surface, and "glued" it to the upper surface:


As the final touch, I straightened the rib edges (it is much easier to draw the texture images on such an "orthogonal" wing layout). The only exception is the skewed inner edge of this wing segment:

When the wing surface was mapped, I replaced the reference image with the standard Blender test image (UV Grid). It is prepared for finding eventual mapping distortions:


As you can see, there was a serious distortion along the leading edge seam.

The remedy for such a flaw depends on the mesh local conditions. When it occurs on a flat surface, you can make the seam line sharp (setting its Crease coefficient to 1.0). However, in this case it would spoil the cross-section of the leading edge. The other, less preferable solution is to insert an additional, perpendicular edge loop. When you locate it in the proper place, it efficiently removes such a distortion:


(I do not like creating such additional edge loops, because each of them makes the resulting mesh topology more complex. However, sometimes you have no choice, as in this case).

In this source *.blend file you can evaluate yourself the current version of the model (as in the first illustration from this post).

Looks great so far!

Outstanding work, as always buddy!

Great research and execution. I've never heard of "Blender" and now have their web page open. I've been learning to use SketchUp along with the Podium Browser to do 3D work. I've never done some thing with compound curves like an airplane, but have been learning to do detailed room renderings and buildings that are then laser-cut to make 1:48 buildings for my model railroad. I like some others were thinking that you were creating a solid model, but making a precise computer rendering is spectacular as well. Your skills are light years beyond mine, but I like learning new stuff. I have a grandson who's getting into 3D animation (he's 12) and Blender could be of great interest to him.

Wurger, Gnomey, Lucky 13, Builder 2010 - thank you for your comments!
Indeed, Blender is a system created for small computer animation studios, which handles the whole process - from the conceptual phase to the composition and postprocessing.

Well, after a long break in August and September (I had to finish a demanding project in my daily work) I am back. This week I made a "slow start": because in my last July post I finished mapping the SBD-3, now I mapped in the UV space parts that are specific to the alternate Dauntless versions: SBD-1 and SBD-5.

Let's start with the SBD-1: when you switch into its scene, you can immediately see the gray elements that are not mapped in the UV space (as in figure "a", below). These parts are specific for this version:


It did not require a lot of work *– just to unwrap few additional meshes in the UV space. You can see them in figure "c", above). I placed their faces in the same location, as their counterparts from the SBD-3. In figure "b", above, you can see the SBD-1 model after this update.

Then I had to make similar work in the SBD-5 scene. The engine cowling of this model contains more differences, thus it required much more work:


When all the meshes in all SBD models were unwrapped, I had to export them into a 2D drawing. (I will need such a picture as a reference for painting various textures). I prefer to keep it as a scalable vector drawing, thus exported it into an SVG picture, which I can edit in Inkscape:


The standard Blender command allows you to export only the single mesh of the active object. Some years ago I wrote an add-on which exports into SVG all selected objects at once. (You can find this add-on and learn how to use it in the III volume of this guide). It is extremely useful for such a model built from multiple objects, like this one.

Inside Inkscape I placed the exported objects onto a layer that has the same name as the defualt UV map in Blender: UVMap. (In the next posts I will prepare in Blender some other alternate UV maps, thus this naming convention is important).

Internally, I split in Inkscape the contents of the UVMap into five sublayers:



Two bottom layers (Color, Common) contains the elements that are common to all three models. I created Color layer for the future use. It contains just the fixed parts of the wing. I am going to use a separate texture for the national insignia and various technical labels. On some SBDs the stars on the wing lower surfaces were so large that they will require the seam line directly on the leading edge. Thus for this purpose I am going to create an alternate UV map for the wings. I will place it in Inkscape on additional Decals sublayer. Then, to create the UV layout for the insignia texture, I will hide the Color layer. When I will need the UV layout for the camouflage texture, I will turn off the Decals layer, and make the Color layer visible.

Why I did not simplify this drawing, creating in Inkscape a separate layer for each texture that would contain all the required objects? Because in such a case I would have to duplicate all of the common objects – sometimes several times.

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The progress of my modelling project is not like a "waterfall", it more like a spiral. From time to time I have to return to a finished stage, and fix something there. That's why I always try to have just "one string that controls all": in this case it means having single instance of every mesh in the Inkscape drawing. When I have to modify something in the corresponding Blender mesh, I will need to update just single element in this drawing, instead of multiple instances in the "simpler" version.

I use the same method as described above for obtaining the UV layout for a particular Dauntless version. There are three sublayers, named: SBD-1, SBD-3, and SBD-5. In each of them I placed just the elements that are specific for these version. For example, the figure below presents contents of the SBD-3 layer:


When you combine it with the basic layers (Color, Common), you will get the complete UV layout for the SBD-3:


(Of course, at this moment this layout contains only the left side of the model. I will update it later, adding the elements from the right side).

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

Lovely work so far!

Wurger, Gnomey - thank you!

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 (as in figure below) 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:


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:


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:


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:
   
   
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2. Resize the mesh faces on this new map by 130% (I typed the exact value of "1.3" using the keyboard input feature):
   
   
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3. Place the enlarged mesh faces as in the reference drawing:
   
   
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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:


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.

Great work so far!

Wurger, Gnomey - thank you!

I always start drawing the image of the aircraft skin by tracing the lines of the main panel seams. They will form a kind of reference "grid", which later I will fill with other details: rivet seams, inspection doors, etc.

I will draw all these technical details in Inkscape, because it is much easier to modify such shapes in this vector-based program than in GIMP, which is mainly intended for the raster images. What's more, I can export this scalable vector graphic from Inkscape to a raster image of any resolution.

Initially I prepared in Inkscape an empty drawing, set up its layer structure, and placed the appropriate links to reference drawings on the UV and Reference layers:


I duplicated here the basic structure for the detailed bump map, which I worked out during my P-40B project. It is explained in all details in the "Virtual Airplane" guide (chapters 3 and 4 in Vol III, or chapters 6 and 7 in the complete edition). In this case I just used the hierarchical layers feature for grouping the related layers (in Panels, Fabric) together. (This feature was introduced in the latest Inkscape 0.9x, while the guide was written earlier, using older versions of this software).

Although I placed my scale drawings in the background, as the reference material, I will not treat them as the "ultimate truth". Everybody makes errors, so do I. The only method to eliminate most of them is to check every detail as many times, as you are able. For example *– see the bent sheet metal strip that runs around the wing tip edge:


When I sketched it on the scale plans, it was a minor detail. Its width was not much larger than the width of the thicker line that I used to trace the outer silhouette of the aircraft. Thus I did not studied the photos carefully enough in that time, and drew this strip too thin. Now I have an occasion to look on the source photos with a "fresh eye", and correct the width of this strip. However, I cannot just offset the original contour from the scale plans. To match the UV layout of the wing, I have to give this curve somewhat different shape that follows the unwrapped area around the wing leading edge (as in figure above).

Well, there is no any "magic" way to do it: I have to keep open Inkscape and Blender side-by-side. In Blender I mapped as the texture the initial image exported from Inkscape (and turned on the option that displays it in the Object/Edit mode). Once I modified this wing tip curve in Inkscape, I had to export the whole drawing to a raster file, and then to reload it in Blender. Fortunately, such a transfer takes no longer than 2-3s. Such an arrangement allowed me to make quickly several iterations, resulting in the proper shape of the curve on the 3D model:


To see better the lines on the model, I drew them in red. Fortunately, the rest of the panel seams runs across relatively flat areas, so they match the scale plans.

Of course, I also matched their locations against the reference photos (I set up them some months ago, and described it in this and subsequent posts):


Fortunately, there were only slight differences, which I quickly introduced to my Inkscape drawing. Such a "double-check" ensures, that the lines are in the proper places, and I can safely fill this image with minor details. However, the common sense tells me, that I should map the panel seam lines on the whole aircraft, first. There is always a chance that I will encounter something unexpected during this process.

Dauntless had large wing flaps, and one of their prominent features were the rounded holes, that perforated their surface. Distribution of these holes determines the location of the internal reinforcements of these flaps, and the corresponding rivet seams. Thus these holes are as important as the panel seams. I started to draw their first row using a special, dotted line:


Although Inkscape does not offer any UI for user-defined dotted lines, I used its XML Editor feature to create a dotted line pattern that matches the holes in the Dauntless flaps. I used here the same method that I worked out for the rivet seams. (See "Virtual Airplane" guide, Figure 3.1.11 in Vol III, or Figure. 6.1.11 in the complete edition, and the further pages referenced there).

Once I drew the first row, I matched it against the reference photos (Figure 64‑5). After a few iterations I received a satisfactory approximation. (Due to various unknown second-order photo distortions, there location of these holes is a kind of "compromise" between various photos and the known location of the flap ribs. The latter were explicitly dimensioned on the Dauntless stations diagram, as you can see Figure 8-3 in this post).

When I matched the first row of the holes, I copied them into another two rows, which I matched against the photo. The final results differ from my scale plans:


It looks that on my scale plans I made a kind of systematic error in calculating ribs stations from inches to drawing pixels. (Since that time, I already made numerous adjustments in this area – see Figure 15-8 in this post, Figure 17-5 in this post, and Figure 31-5 in this post).

The general panel layout on the wing top surface is similar to the panels on the bottom. Thus I copied (and mirrored) their lines from the bottom surface. It required just a few minor adjustments to match their drawing to the photos of the wing top surface:


(I was really happy that I did not have to match again the wing tip strip against the photo. The curve copied from the bottom surface fits the top surface quite well).

For the further test, I created a copy of the texture image with a semi-transparent background. It makes the model surfaces transparent (as in figure "a", below):


I used this effect to check if the panel seams that runs along the wing spars on the top surface match their counterparts on the bottom surface (as in figure "b", above). (It will be useful, when I start to recreate the wing internal structures).

During further checking of the results, I noticed a minor error on the leading edge:


This is a side effect of the corner in the mesh seam, which does not run along a "sharp" (Crease = 1) mesh edge. Unfortunately, I have to keep this edge smooth, because it controls the proper shape of the wing leading edge, especially in the top view. There are two solutions: 1. add two additional "ribs" on both sides of this wing tip rib, to remodel this mesh fragment, 2. create the strip along the wing tip as a separate object, and placed it on the main mesh. I still have to decide, which solution is better.

Figure below shows the results of this week: the panel lines of the wing and the image of the flap perforation:


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

Next week I will map at least the wing center panels and its flaps perforation. (Maybe I will do more – but I am still short of time due to a certain project in my daily job).