Skinners, a question: why do we use rivet layers?

[Original_Uwe]

Not saying we are wrong to but it's something I've wondered about for a while in my own struggle between accuracy and beauty with aircraft skins.

A (very) cursory search on the size of aluminum aviation rivets shows sizes around the 3/32" mark. That's tiny by any standard but atomic. Are our skins, even in 4K, capable of depicting such small scale?

 

Furthermore looking at pictures from the war the aircraft (Luftwaffe in my case) and of their modern restorations and museum pieces, the rivets simply don't appear most of the time. They are painted the same color as the rest of the aircraft though may show in reflections, I'm not sure. The aircraft are also largely cleaner than we paint them even in war time photos.

 

So what are we going for in using them? To highlight those parts of the aircraft, to add a texture to the planes, or simply to please the end consumer?

I'd love to hear any and all input. I'll continue to use very mild panel lines and highlights but I think I'll mostly shy away from rivets for a while and experiment.

 

ETA: Of course this could simply be an issue of resolution in old photos, but even in new high def photos I can clearly identify the rivets only by zooming way in, as if standing mere feet away from the aircraft.

 

ETA2: Or perhaps a matter of darker colors showing them less than say RLM 76?

Edited March 18, 2017 by 1./JG54_Uwe

[RaFiGer]

@1./JG54_Uwe

 

That's a very interesting question, because I feel the idea of doing paintschemes for any machines especially for warbirds is to have them as accurate as possible and the dedicates modellers or skins what to show that their work is "living". So the use of riviting & wheatering is mandatory to have these effects of a true model in real or digital.

 

For myself, with visiting war museums around the world and seeing also the nice "new" painted and maintenant Warbirds feel that it is necessary to have rivets visible on skins

 

This discussion with some examples reflects my own understanding and opinion pretty good:

 

http://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/10341452-sist-fw-190-a8-schwarze-8-a-3.html

 

But still you have to decide for yourself, it is a way of art & believe

 

Greetings

RaFiGer

[Original_Uwe]

I should have added that why paint the rivets when we can actually put "on" the plane now via normalmaps and alphachannels.

Of course in certain areas where grime accumulates like the areas exposed to exhaust there will be some dark grime accumulation. For the rest of the aircraft however we can actually make it a part of the planes "metal skin" rather than just paint if you catch my drift.

Thanks for the link, ill be sure to check it out!

[BOO]

Hi

 

Rivets add interest but I agree wouldn't be so apparent in many of the RL aircraft. That said, I like rivets and whilst I do try to be a little subtle with them, their inclusion is something ive carried over from kit building.  

 

Its a balance of art and reality I guess but with the 4K normal maps perhaps its something that can hinted at in the light reflections better.

 

Personally, i'll still include the rivets though as its my taste.

 

Regards

 

BOO

[6./ZG26_5tuka]

There are different kinds of rivets. On most fighters you've got countersunk rivets (often patched up with putty on german fighters) for a smooth and aerodynamic surface while others may use normal rivets with extending heads. Example pictures below are from the Hendon Stuka which clearly shows dirt accumilation around the countersunk rivets.

 

 

 

 

Also it's not as easy as to say normalmaps could take care of it all and make it look more realistic. Due to the limitations of the ingame lighting reflections don't always appear in places where you could in reality depict some light coming off the surface from secondary light sources. In such circumstances the skin would look plain and flat depspite the normalmap modeling all rivets, panel lines ect.

 

That's why we have rivets and stuff as overlays for the diffuse texture. If you highlight the rivet heads and darken the rivet borders slightly you can compensate for the flat look the plane would have in certain lighting conditions.

 

Where this became very apparent to me was when doing the corrugation on the Ju 52. Even though this could be handled by the normalmap entirely I found that without a shading layer for the diffuse texture it would look flatout wrong at certain angles and ingame lighting.

Edited March 18, 2017 by 6./ZG26_5tuka

[Original_Uwe]

Frankly I hadntconsidered aircraft other than 109/190's, as those are the ones that hold my real interest. Damn the 87 is an ugly bird lol.

The normalmaps do a pretty good job of giving the overall impression of rivets, Ill post my WIP F-2 normalmap later. Very much WIP but the effect is quite nice in conjunction with some light weathering.

[Original_Uwe]

As promised, my demonstrator.

This is simply to demontrate the effect. Skin is for the 109F-2 and is a WIP for some of the weathering layers Im working on. Its a 2k heavily modified version of BHH's F-2 template.

 

In it Ive painted no rivets on except for those where they would collect soot from the exhaust on the fuselage and wing roots, otherwise all rivets are from the normal map.

Download includes a skin and new normal map with folder backing up the original N.M. simply drop in and overwrite, and then when your done you can delete it and go back to the stock version.

I rather like the effect because the rivets are very clearly there but they aren't overstated or drawn on, but rather look like an actual part of the aircraft skin.

 

 

http://www.mediafire.com/file/5iaj4y3eca97wy8/data.7z

[ICDP]

Hi Uwe.  I had a test of your demonstrator and to be honest it looked very flat and featureless at most angles.  You have demonstrated an issue that renders (pun intended) exaggerated details and textures in games, as a necessary compromise.

 

Do we paint on exaggerated tiny details, even when in real life, from some angles and distances they become invisible?  I believe that for now, even at 4k that the answer is yes.  Because in real life we aren't limited by low resolutions and extremely simplified lighting.  In real life, if you get even reasonably close you will make out every rivet very clearly.  If you leave them out in a sim and zoom right in, you end up with a flat featureless textures when in reality you should be seeing detail.

 

I have attached some images, one from a clean Fw-19-A3 created using my template and 4k normal map.  At this distance the rivets are barely noticeable and in no way (IMHO) overdone or false looking.The others from WWII era Fw190-A's that show rivets can be clearly visible, even at moderate distances.

Edited March 19, 2017 by ICDP

[Original_Uwe]

Well flat and featureless is rather the point of flat clean metal lol.

 

Here's a 190 at about the same angle and distance as your A-3.

Fresh off the restoration line!

 

A bare sheet of aluminum, painted in whatever color you wish, is flat and featureless except for the texture of the paint. As in the picture above the plane only shows details of panel lines but not in color, only really how they reflect light differently than their adjacent panels and the gaps between them. Rivets except for the largest ones are not plainly visible. However if we walked around the aircraft at close distance we would see the rivets as surface dimples in how they play with ambient light.

Now take that aircraft and fly a few sorties and you'll see grime start to accumulate in the rivets and panel lines from engine exhaust, gun smoke, oil leas, etc. Areas not exposed to such influences would of course remain very indistinct.

 

To each their own I suppose, and as someone who enjoys your templates I say many thanks for all your doing!

 

Edited for more pictures: I particularly like the last one. We can see the tail section and fuselage at fairly close range and though we know there are several riveted panel lines on the tail none are readily apparent and it is rather flat and featureless. Exceptions being in the wing root with much larger rivets and screws or the attachment point of the horizontal stabilizers.

 

Edit2: I'm definitely going to remove some of the access hatches and holes from my normal map, those would look better painted on I think.

Edited March 20, 2017 by 1./JG54_Uwe

[ICDP]

I totally agree Uwe, it can look flat and featureless in real life as well, but as you get closer the detail of rivets jumps out.  If you go for flat and featureless on a texture in a game, it ends up looking flat and featureless.  In a game you have to compromise because you have serious limitations compared to how things look in real life.

 

So it's a compromise.

 

The screenshot I posted shows that if you are subtle you can achieve a very good compromise and in certain areas the rivets are invisible at that angle and distance.  Zoom in a bit and the rivets become much clearer.

Edited March 20, 2017 by ICDP

[6./ZG26_5tuka]

Those are Flugwerk 190s, not restored ones. The reason why you can't see the rivets is because they're patched up which wasn't common for all aircraft in WW2 (in late war germans even abandoned patching up rivets on fightes to decrease production time).

 

There are a good ammount of pictures clearly showing lines of rivets and other detail but it's difficult to come across good WW2 photography that allows to spot such details. Either way, like ICDP says, it will depend on taste. Both solutions involve sacrifises and there isn't really a 'better' or 'more realistic' approach in making those details.

[BlackHellHound1]

Rivets are a difficult thing to get right. There are lots of different types of production techniques that create different effects on aircraft (and non-aircraft).

To get mine right I had to do a lot of research. Looking at modern planes, still existing WW2 planes and images from WW2. 

It is indeed true that from some distance, (few meters is usually enough) the rivets become completely invisible. But if you are in the cockpit, you can clearly see the individual rivets. 

These rivets usually become visible because of a few thing. 

• Rivets have a tendency to be a tiny bit shinier than the metal around them. Usually, because they are made of slightly different metal alloys.
• The metal around a rivet is usually warped a bit due to stresses in the metal and heat-warping.
• Dirt and dust collect around rivets that are often stepped on or in area's where airborne dust comes in contact with the plane. (dust that is kicked up during landing and takeoff for instance)
• The rivets themselves are often the same colour as the surrounding and don't stand out themselves due to colour similarities.

When making my rivets for my templates, my goal was to make the rivets visible because of the above-mentioned reasons and not to give the rivets themselves a different colour. 

A combination of effects on the skins, alpha channel and normal map make this possible. 

 

Let me explain each effect that I used on each layer. Keep in mind that all these effects are quite lightly done as to not overdo the effects.

 

On the skin texture themselves, I added 2 effects, the first being a light shading effect around the rivet (not on the rivet). This effect creates a slight metal warped look around the rivet when viewed from a close distance.

Secondly, I added dirt effects around the rivets in places where dirt would build up. These dirt effects make small areas of rivets visible in most situations where light does not affect the surrounding metal. These are the rivets with a lot of dirt buildup around them. 

The rivet themselves are completely invisible on the skin texture. The rivets have the exact same colour as the surrounding metal. All you see is the surrounding dirt and metal deformation.

 

On the Alpha channel, I added the effect that would make the rivets shine just a little more than the surrounding metal. This is the only effect that is actually on the rivet itself. It only becomes visible at very close range, when you lean out of the cockpit for instance.

 

Last but not least, the rivets on the Normal Map once again stand out because of metal warping when the sun hits the skin from the correct angle. You will once again only see the warping of metal surrounding the rivet and not the rivet itself. This effect is a bit stronger in some areas where more metal warping would occur.

 

As a result of this, the plane shows different effects depending on how the rivets are looked at and how the light shines on them. In some situations, this does mean that sometimes the plane can look flat but at other times the plane looks quite bumpy. Similar to effects I found on many different planes both new and old. 

 

The combination of these effects creates a nice approximation as to the real life rivets, although, it is nearly impossible to fully accurate display the rivets on an aircraft in games. 

A perfect way to make rivets does not exist. There are many methods possible that make a rivet visible.

 

To be honest, I do believe that some methods make more realistic rivets then others. However, this does not instantly mean that they are better. I have tried many effects that are more realistic and some of them looked like crap. 

 

I hope this makes my point of view clear.

 

BlackHellHound1

 

[A-E-Hartmann]

I'm OK with BHH.
Depending on the effects.

 

[BOO]

Would the effects of dirt accumilations and the depositing of "gunk" in the divots resultant from the "simonzing" of some aircraft also effect the overall look?

[ICDP]

Well as BHH ans Hartmann have said, there are many variables and compromises involved in making rivets look realistic.  I have seen very clear images of WWII aircraft and could not see a single rivet, on some others the rivets are as clear as day.

 

It's all down to personal preference how to depict rivets on skins/templates but pretty much all skinners include them.  IMHO It looks far stranger to zoom right into a plane in a sim and find no rivets, than it is to have slightly exaggerated rivets.

[A-E-Hartmann]

It is true that on some photographs, we do not see too rivets.
But do not forget that the photogaphy are black and white and not of good quality.
And the angles of view are quite distant.
Here is a photograph that I have used as refference .