PDA

View Full Version : Modelling visual stealth



03-19-2004, 01:04 AM
I have found that aircraft color has absolutely no effect on how noticeable an aircraft is at 1-pixel-speck range. Bright white and dark black aircraft both appear equally well when viewed at speck range.

Aircraft in this sim at very low LOD tend to appear as generic gray dots regardless of what color they are when seen up close. It's a good approximation and gets the job done very nicely for this sim.

The problem is, in reality aircraft luminosity DOES have an effect how how easy it is to spot an aircraft. Light gray aircraft are hardest to see against low altitude skies. Darker colors hide better against dark high altitude skies. Colors are not very noticable at great distances, so gray is just fine against terrain as well. The key thing is how dark or light the aircraft is.

In "the next sim", it would be nice if aircraft speck visibility depended on the aircraft's color. Black airplanes at low altiude stick out very clearly in all lighting conditions, even at night. White aircraft work OK against snow, but otherwise are also very easy to see. Neutral grays and pastels work best.

As for historic relevance.... Visual stealth was not unknown during WW2. Notice how bombers quit using black undersides partway through the war. They realized that a big black silhouette is way more noticeable than a lighter colored underside, even at night. The RAF apparently had a good idea what worked at various altitudes, too, as they used PRU blue for high altitude recon birds and PRU pink for low altitude.

03-19-2004, 01:04 AM
I have found that aircraft color has absolutely no effect on how noticeable an aircraft is at 1-pixel-speck range. Bright white and dark black aircraft both appear equally well when viewed at speck range.

Aircraft in this sim at very low LOD tend to appear as generic gray dots regardless of what color they are when seen up close. It's a good approximation and gets the job done very nicely for this sim.

The problem is, in reality aircraft luminosity DOES have an effect how how easy it is to spot an aircraft. Light gray aircraft are hardest to see against low altitude skies. Darker colors hide better against dark high altitude skies. Colors are not very noticable at great distances, so gray is just fine against terrain as well. The key thing is how dark or light the aircraft is.

In "the next sim", it would be nice if aircraft speck visibility depended on the aircraft's color. Black airplanes at low altiude stick out very clearly in all lighting conditions, even at night. White aircraft work OK against snow, but otherwise are also very easy to see. Neutral grays and pastels work best.

As for historic relevance.... Visual stealth was not unknown during WW2. Notice how bombers quit using black undersides partway through the war. They realized that a big black silhouette is way more noticeable than a lighter colored underside, even at night. The RAF apparently had a good idea what worked at various altitudes, too, as they used PRU blue for high altitude recon birds and PRU pink for low altitude.

Dmitri9mm
03-19-2004, 01:44 AM
Actually I've heard that RAF started using lighter undersides late in the war because total air-superiority made it possible to bomb both night and day.
An example of relevance on the other hand might be the german so called "high-altitude fighter escort" very fast planes (usually bf 109 G-10 or K-4) that was supposed to fly above the Staffels attacking enemy bombers, providing some sort of protection against P-51 scorts.
These aircraft where painted some sort of RLM light grey og sky-blue all over to ensure that they were spottet only in the last moment.
This is an example of relevance.

03-19-2004, 01:58 AM
Okay, maybe RAF didn't realize at the time that black undersides made them easier to see.

You're right that light gray and blue works very well. It's a shame that shading does not affect visibility of 1-pixel specks.

IAFS_Painter
03-19-2004, 01:58 AM
Interesting ...

That would be affected by whether skin dl is enabled? At both client PCs?

A single tone value could then be calculated for the a/c for each of top and bottom views. Remember, R, G, and B values are identical for Greys - so we only need one byte for grey.

One byte each for top and bottom aspect of the plane.
Double that to allow for client with skin D/L on or off.

That's two, two byte messages (or maybe one four byte message), sent when a plane spawns.
This is trivial in terms of the data transfered during on-line play - the wrappers for the message would be bigger than the message content. (Thinking about it, 12 bytes - 3 x 4 -would be OK.)

Spawn time for a plane would be longer - for a plane that is spawning - but not significantly (not compared with spawn bounce .. as the A/C finds the ground).
Spawn lag at the foreign P/Cs would be a couple of nano-seconds longer - not significant in our terms.


That may work - wonder if Oleg's team will pick it up?

http://www.robert-stuart.me.uk/il2/signature/paint_sig_003.jpg
il2airracing.com (http://www.il2airracing.com) Painter's Pages (http://www.robert-stuart.me.uk/il2)
I've given up correcting my own spelling
Unless I've corrected it here

BlindHuck
03-19-2004, 03:17 AM
They were painting the bottom sides of B-29's black in WW2 and Korea.

"I race full real exclusively in IL2:The Forgotten Battles." - Mark Donohue

03-19-2004, 04:38 AM
Darker colors work better at extremely high altitudes, but black is too dark.

B-52s in SEA were for a time painted dark GRAY on the underside to reduce visibility at 35-40 thousand feet. Modern B-2s are also dark gray for the same reasons, and fly at the same altitudes. At those altitudes the underside is well lit by scattered light from the atmosphere below. Against a deep violet sky, you need to be a bit darker to reduce your silhouette. B-2's even have a photosensor on the top of the aircraft that helps the match the color of the sky by adjusting altitude.

Painting those Korean-era B-29s BLACK is a throwback to the days when people believed black helped you to be invisible at night, or to evade searchlights. It's a hard incorrect belief to kill. USAF generals insisted for years that F-117s be painted black. Only now are they finaly getting practical pale gray paintjobs.

rgoodrich1978
03-19-2004, 05:20 AM
But black looks so darn COOL! hehe

http://www.revell-monogram.com/store/ModelDetail.cfm?Id=237&SubjectId=2&SkillId=3&ScaleId=0&TypeId=10&StartRow=9&FromSearch=1

-PURGE-
its good for you

SUPERAEREO
03-19-2004, 06:12 AM
The black paint on the lower surfaces of USAAF bombers was very glossy and was adopted because during trials it showed a remarkable ability in hiding aircraft from enemy searchlights.
The light was partly reflected away from the plane, and this helped in not creating a visibly darker silhouette against the illuminated portion of the sky.

On the other hand, Luftwaffe and then RAF nightfighters were painted in light tones of grey with a disruptive mottle (pattern for the RAF) of a darker colour (green for the RAF).
Their overall light appearance made them far less visible in the moonlight and against a cloud background.

S!



"The first time I ever saw a jet, I shot it down."
Chuck Yaeger