Technical: a guide to create rivets

[Chris B]

Thanks you Chris! I am sure this will help many repainters here to create some good rivets. Time to experiment with layers again!

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Windrunner asked if I could do a tutorial on rivetting.

PART 1 - GENERAL BACKGROUND

Lord knows why, it isn't difficult - well, except for placing several thousand rivets on your plane ;D

I use Corel Photoshop / Draw, but the same functions exist in Photoshop, so anything I put here is "translatable" - you'll just have to do a quick search of the various menus.

The other problem i have is that I use a German language version of Corel, so i may not have the right words in English - perhaps someone can come to the rescue here and give us a clue.

First: what types of rivets are there?

Basically (I'll not go into Avdel, bifurcated (Tucker pop) or others) - just the shapes:

1. Countersunk
2. Dome head
3. Half round.

The latter two differ only slightly - the dome headed rivet heads do not stand so proud above the aircraft skin. The countersunk is flush with the aircraft surfact.

When a plane is new, countersunk rivets are as good as invisible under the paint, so there's nothing to do on a countersunk rivet skin - unless it is an older plane.

What happens (and this is for all rivets) then, is that as the plane flexes during use, the rivets work and the paint is cracked off around the circumerence of the head. The first thing is you get a dark circle around the edge of the rivet.

All raised head rivets also have a lighting factor to consider as well.

We can't create rivets (yet) which have highlights and cast shadows. Another thing we can't do well is to show the circle of dirt under older rivets.

Another thing that can happen, is that the fitter installing rivets can sometimes hold the dolly (reaction tool) at an angle and make a sharp crescent shaped dent in the skin (mind you, he'd fail his trade test if he did). We're not going to do that. Are we?

One final caveat. These tips are only aimed at textures that are big enough to allow half way decent rivet effects - and that, currently, means the Dornier DO27 from Digital Aviation. I you know of other texture kits that use three panels to cover a little over 9 metres, then let me know. The Dornier fuselage side has 2650 pixels length, so we can get down to some nitty gritty detail here.

[Chris B]

PART 2 - LET'S GET DOWN TO IT!

But first the panel lines!

This is straight forward - 1 pixel wide lines, no anti aliasing. You can come back to these later and create light effects in exactly the same way as described below for the rivets - just remember, the highlight on a gap between panels is on the opposite side to the highlights on the rivet heads. Think about it - the lines are depressions.

Now...

In your Vector drawing program (Draw / Photoshop) just draw a circle about 12 pixels diameter.

Copy this into the photo edit part of your program - in the Corel case, I have to copy/paste from Draw to Photopaint

Make two copies of the circle - one, above the other twice

Bottom circle:

Give it some Gaussian blur so that the blurry circle is about two to three times the diameter of the original

Distort this vertically so that it is an ellipse equal in height to the original rivet.

Mask the lower half of this and "Create new object".

Make the bottom half slightly lighter than the top half

Give both a merg factor of "multiply"

This gives a slight dimple effect to the aircraft skin

Middle layer circle:

Give this a merge factor of "multiply" and make its "coverage" value about 50%

Top layer circle:

Give this a merge factor of "Farbe Ausweich" (The German word... some form of blend, but nut burn, subtract, divide...)

Now move the top circle up one and left one pixel and hey presto, you see a three dimensional effect!

Done! (You have been ;D) Now comes the hard part! - long lines of rivets...

copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste, copy / paste.....

Tips:

Copy paste on, then two then four, then eight...

Make two lines of about twenty rivets - no more. One horizontal, one vertical. That way the light direction stays the same. Rotate a horizontal line and you'll change the lighting effect. Not good!

Now you can copy / paste in twenties. More if you do long lines.

Keep a couple of singles around - you'll need to place some rivets around the edges of circular panels.

END OF PART TWO - bear with me while I go away and make some screenies...

[Chris B]

PART 3 - THE PICTURES

I drew, copy / pasted my circles in Corel Draw and then copied them over to Paint - either way is OK... Whatever you are comfy with. Here's all the circles in the place the rivets should be:



Transfer these to the Paint program...



Add the rivet lines



Make three layers of rivets - one above the other twice...

IMPORTANT NOTE:

When you draw your rivets use zero outline and make the colour fill something pastelly. I use purple simple because this is the colour that real world aluminium rivets are for the aircraft industry. Magnesium alloy rivets are green, Titanium blue (or something like that)... I can't remember all the colour codes... ;D

NOW, in your painter program, reduce the intensity to zero - the rivets will turn grey. Play around a bit with light and dark till you get something like this:



Do the Gaussian blur on the lower rivet layer:

(I left out the "split the gaussian bit" - you have to do just one rivet in the paint programme first and then multiply...



Now do a "Multiply" on the second layer - in this case I changed the "Coverage" value to 15 instead of 50... It's all trial and error and taste as you will see later



Now do "Ausweich" on the top layer...



Now displace the top layer up and left - or right, as is your wont and need...



Now do the same for the panel lines



Turn the default rivets layer off on the texture



You can change values of "Multiply" and "Ausweich" for the rivets and you get stronger lighting effects.



DONE...

All that is left for you to do is to wrap the skin onto your model...

WHAT I HAVE NOT DEALT WITH HERE!

For the purposes of the excercise I have used larger rivets. The scale on the DO27 is not that big.

Also: Too much lighting efect can make the rivets too emphasised.

Also: Some lines need to be darker than others - some skin panels are thicker and have correspondingly larger shadows and gaps.

Here's my "Work-in-Progress" shot of the work on the DO27

Note:

Different rivet pitches according to what they are holding.

Panel lines according to thickness

Final tip - ALL rivets and panel lines should go above the paint, but below the dirt, reflections, oil smears etc.





HAVE FUN

[windrunner]

After reading your thread, it seems that I'll have to make my way around it. I have Photoshop too, and there's no problem to "translate" the technical tems into my program it's easily understood (wich, btw, is into german too).

But if someone has another paint program in another language, don't doubt to ask about it, we'll find a way to sort it out!

[Chris B]

Hey, now that's interesting. Can I do that with a three layered single rivet in Photopaint? I don't know, but I'll find out.

[windrunner]

With photoshop you can open a file with multiple layers like a single layer one, by clicking ctrl+alt+shift while opening it. Not sure how to do it with Photopaint.

With a single layer now, you can add as Shad suggested as a new brush, Not a bad idea at all.

[redruffensore]

Dad-blamed wonderful Chris, soon I am going to have a portfolio of your tutorials, which BTW are top shelf!

I have copied and pasted this one into Open Office and converted it to a .pfd for hard copy.

A little bump texturing for FSX planes that have such and bang, those rivets will stand out or recess like you want them to. Kudos my friend.

I think the German "Ausweich ferbe" in relation to one's graphics program means "Invert Colo(u)r". Not positive, I'll let a native stake his life. ;D

Caz

[Chris B]

Hellooooo... I've got followers popping up everywhere everywhere

This tut was originally for FS9 to give "pseudo rivets". It does exactly the same as bump mapping does - except for using the alpha channel to give them that third dimension.

And yes, using the "offset" ideas will give a lot of extra pseudo depth even to dds bumpmapped models.

Thanks for dropping by here Caz.

[redruffensore]

I tag in here on occasion, because well, I happen to like FSGW3 and have all of my North American FSGenesis 38-meter mesh installed for it. Most all of my old crates are stored there, in addition to Joe Binka's excellent Old Rhinebeck. And like FS9, the frame rates are smooooth. ;D Plus Bill gives me plenty of barns to fly under with the Curtiss Jenny and scares the bejesus out of those chickens! ;D ;D

Seriously Chris, I have learned much from the likes of you and others here and at Sim-Outhouse. At Screenshot Art too. I now do my own prop washes from what I have learned from Bob Rivera. I owe a note of gratitude to all you fellas; Stuart Green, Huub Vink, Bill Lionheart, and most of all to the late Leon Lewis, who first got me interested in doing repaints for FS2002 aircraft way back in the day. Without his guidance over emails, I may have never reached the level I have attained to this day. May God bless and keep him.

Caz

[Chris B]

Yerst... Here's to Leon!