Bump Maps Are Blue

[Alky]

1) Why are bump maps blue?
2) How do you make a bump map?

Thanks!

[adlabs6]

Hi, an interesting question.

Which sim BTW?

This is an area that I do not know about either. I should do some research on it.

[Alky]

Hi, an interesting question.

Which sim BTW?

This is an area that I do not know about either. I should do some research on it.

I'm mainly interested in FSX but I think bump mapping is used in a lot of computer art.
From what little research I've done since my original post it appears there are some methods to creating bump maps but the most effective way is by creating it from the original 3D model. So, I think it's above my pay grade! LOL
I have no clue why all the ones I see in FSX are blue though!

[adlabs6]

Did some more reading.

It would appear that FSX bump maps are created to allow use of DDS/DXT5 compression, which otherwise would (so far as I understand) foul up the bump data during compression.

Since FSX has to worry with a huge number of textures and maintain good performance, the compression of textures is more important that say... A bump map for rendering a still image, where you can have a high quality uncompressed texture and not worry much about it slowing much down.

Also, check on the part of the first link below regarding normal mapping vs. bump mapping. It indicates most of why what FSX uses (normal mapping, not bump mapping) has the blue and purple colors, vs. an 8 bit gray scale 'bump' map.

Here are some posts about it:

Bump (Normal) Maps for FSX | FSDeveloper

Normal map creation - FSDeveloper Wiki

[Alky]

Here are some posts about it:

Bump (Normal) Maps for FSX | FSDeveloper

Normal map creation - FSDeveloper Wiki

Thanx for the links, I'll have a look and see what I make of it.
Your post makes some sense, I was looking at doing a repaint on a Carenado Cessna 340a which I notice has no bump maps. I thought it was just because it was an older model.
Speaking of models, I saw your thread on the Mustang model, very impressive! Back in the day, (early 60's) when I was about 16, my best friend & I used to get together and build AMT models with that kind of detail. A local hobby shop ran model car contests every few months and we'd enter and try & out do each other. One of us always won first place.
We used to do customize the bodies using plastic wood and then use liquid aluminum as a final filler. When sanded out, the body was glass smooth. Then we used, believe it or not, lacquer automotive paint to finish them off. There's a trick to using lacquer without the plastic model turning into a blob.
LOL
Can't wait to see your results!

[adlabs6]

Hey, yea my Dad was into model building back in those days, too. The hobby seems to have been pretty active during those days. There is loads of coverage in my collection of Rod & Custom magazines from those years.

Automotive lacquer... wow.

I should be getting some primer and maybe some red acrylic base coats down this month. I too am excited to see how that goes.

[Alky]

Automotive lacquer... wow.

I should be getting some primer and maybe some red acrylic base coats down this month. I too am excited to see how that goes.

Back in the day automotive stores stocked touch up paint in spray bombs and there was a zillion colors to choose from. The secret was patience, you had to "dust" a few layers on till the model was covered. If you laid it on shiny, the model will melt. Once you got the color on and it's dried at least 24 hours, you can go ahead and paint. I used to get a nice smooth glossy finish and then use toothpaste to rub it out. After that a couple of layers of clear coat and you had a show winner

[Skyraider3D]

Are you talking about normal maps by any chance, which have a violet colour by default (RGB 128,128,255)? These maps define the angle of the normal of the surface on which it's mapped. The default colour corresponds with the normal of the underlying polygon (i.e. perpendicular to the face), but this angle is modified by change of RGB value.
Also see Wikipedia for a more technical explanation:
Normal mapping - Wikipedia, the free encyclopedia

How to make them? Either you can generate them from a 3D model by calculating the difference in normals between a high-detail model and a low-detail model (thus the low-detail model with the resulting normal map will look similar to the high-detail model), or by converting a hand-drawn bump map (which are grey). Pixels on bump maps represent a height rather than a normal angle, hence one colour channel is sufficient for them. Nvidia has a freely downloadable plugin for Photoshop that allows you to convert a bump map into a normal map:
https://developer.nvidia.com/nvidia-...dobe-photoshop

Various dedicated software packages exist that are designed to create normal maps too.

[Alky]

Also see Wikipedia for a more technical explanation:
Normal mapping - Wikipedia, the free encyclopedia

Nvidia has a freely downloadable plugin for Photoshop that allows you to convert a bump map into a normal map:
https://developer.nvidia.com/nvidia-...dobe-photoshop

Various dedicated software packages exist that are designed to create normal maps too.

Thank you for the response. In my ignorance of the subject, my original post was a bit general. Since then I've looked at some some links provided including yours and have come to the conclusion that the whole subject is well beyond my pay grade and comprehension.
Thanks again!