Bump map help need!

[Duckie]

Hello all you talented painters. I need some help, please. I've gone through this process probably hundreds of times but have never run into this before.

I'm trying to create some new bumps and am getting “artifacts” in the final bump texture. Below you can see the before and after. The before is the generated texture using the nvidia conversion process which creates a “master” texture in bmp format. In PSP the master is split into three RGB textures. A few processing steps later the 3 RGB textures are then combined into a refined master with a separate ALPHA texture being produced in the process. That is what the BEFORE texture below is.
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The AFTER texture is that same “BEFORE” texture that has been converted to DDS format along with the ALPHA texture, placed into the aircraft texture folder then loaded into the sim (FSX). The light and dark backgrounds around the rivets in the AFTER also appear in sim on the model and destroy the appearance of the aircraft in sim.
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I’ve never run into this before and I have not been able to figure it out. Suggestions would be very appreciated.


Thanks,

Steve

[DaveQ]

Hi Steve. Like you I've done this many times but I use the the Nvidia plug-in in Photoshop, so I can only offer limited help, and, in any case, you're much better than I am at this!

It looks to me as if one of the channels has corrupted during final conversion to .dds; best guess would be the alpha channel. Have you checked the channels for distortion? I have sometimes found that copying rivet lines distorts them quite badly in older versions of Photoshop so you could look at how you copied, say, the red channel to a new sheet for the alpha channel.

If you use Martin Wright's Dxtbmp app. to convert maybe you could try a different dds conversion tool. I guess, as a last resort, you could take a trial of Photoshop and the Nvidia Texture Tools plug-in; I can walk you through it.....!

Best of luck

DaveQ

[Duckie]

Hi Steve. Like you I've done this many times but I use the the Nvidia plug-in in Photoshop, so I can only offer limited help, and, in any case, you're much better than I am at this!

It looks to me as if one of the channels has corrupted during final conversion to .dds; best guess would be the alpha channel. Have you checked the channels for distortion? I have sometimes found that copying rivet lines distorts them quite badly in older versions of Photoshop so you could look at how you copied, say, the red channel to a new sheet for the alpha channel.

If you use Martin Wright's Dxtbmp app. to convert maybe you could try a different dds conversion tool. I guess, as a last resort, you could take a trial of Photoshop and the Nvidia Texture Tools plug-in; I can walk you through it.....!

Best of luck

DaveQ

Hey Dave. Thanks very much for the reply. I believe you're correct re corrupted channel.
I use the Nvidia plug-in with PSP, and PSP has provisions for using that tool (and others) and accepts that tool without modification or conversion. My PSP version is 2021. I believe its the final bump channel (BLUE) that's being corrupted. Comparing it to others with the same RGB coding characteristics the final blue bump texture RGB code should be 0-130-255, however its 0-128-255. The final ALPHA texture code matches others with the same characteristics and is 128-128-128.

My process is:
1. using a bmp texture of panel lines (varying of black) and rivets (varying shades of white) on a 128-128-128 background I run this through the Nvidia Normal Map Filter which gives a purple-ish - blue relief texture.

2. I then run the resultant texture through the PSP RGB Split Channel process which gives a gray texture titled RED; another gray texture titled GREEN; and a third texture that is white titled BLUE.

3. I save the RED texture unmodified as the ALPHA

4. I then fill the RED texture (which is still on my desktop) with black 0-0-0

5. I fill the BLUE texture with white 255-255-255

6. The RED, GREEN (unmodified), and BLUE textures, all of which are still on the desktop, are then recombined using the PSP RGB Combine Channel function.

This process produces what I'll call the "final" blue bump texture. The ALPHA texture used is the RED channel which was saved earlier in step 3 above. The Final blue bump texture RGB coding is 0-128-255 instead of the more usual 0-130-255. This is where I think the corruption is happening.

EDIT - UPDATE: After some more testing I now believe the corruption is happening in the DDS compression/conversion process.

I've performed this process probably hundreds of times using same process, programs and apps without a hitch. This is a real head scratcher.

Couple of questions if you don't mind.

1. What settings do you use with the Nvidia Normal Map Filter plug-in

2. What is another dds conversion tool to use.

Thanks ,

Steve

[DaveQ]

I've sent you a PM with a link to two .dds conversion tools; they're very old but might do the trick. My methodology for making bump maps in Photoshop exactly mirrors yours so no issues there, though the plug-in works directly from the .psd file.

In the Texture Tools Exporter plug-in I select normal map - tangent space, height source - average RGB, height generation - makes little difference, and Wrap selected.

Only one issue, the right side is indented where black, left side raised. But I don't let that bother me too much - I rarely publish anything these days anyway.....

Good Luck!

DaveQ

PS - If you like you can send me the .bmp and .dds files; I could have a look-see with Photoshop, see if I can spot anything.

[Duckie]

Thanks Dave. Got your PM and will send the texture files later today. Thanks very much for the offer.

Steve

EDIT: PM sent.