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Alpha channel woes (Read 669 times)
Feb 12th, 2010 at 7:36am

LeeC   Offline
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Hi All,
Am trying my first foray into adjusting the shininess of a plane by tinkering with the alpha channel, but everything is going pear shaped.

For some reason, changes to the alpha channel end up lightening or darkening the model, rather than making it more/less shiny.

I am using Photoshop CS3 with the NVidia DDS plugin. I am exporting the texture as a DXT5, ARGB, 8bpp, Interpolated Alpha. Now that in itself could be the problem as I can't find any definitive info on what format to save the textures in. I did a search for "texture format" in the forums and got one result.  Sad

I know the aircraft I am working with handles the matte/shiny value, as the variations have different levels of shininess (and have alpha channels of different shades of grey).

Any help is greatly appreciated.

Cheers
Lee C
 
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Reply #1 - Feb 12th, 2010 at 8:40am

Frequent Flyer   Offline
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Does it change ONLY the darkness/brightness or does the shininess change too?
 

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Reply #2 - Feb 12th, 2010 at 8:51am

LeeC   Offline
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Just the darkness, the shininess remains the same.
 
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Reply #3 - Feb 12th, 2010 at 4:29pm

Bruce448   Offline
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LeeC wrote on Feb 12th, 2010 at 8:51am:
Just the darkness, the shininess remains the same.




The way I do it, is to save it as a .psd and convert the files to .dds5 using imagetool (found in the FSX SDK, it automatically flips the texture for you).


Bruce
 

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Reply #4 - Feb 12th, 2010 at 4:57pm

LeeC   Offline
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Bruce448 wrote on Feb 12th, 2010 at 4:29pm:
LeeC wrote on Feb 12th, 2010 at 8:51am:
Just the darkness, the shininess remains the same.




The way I do it, is to save it as a .psd and convert the files to .dds5 using imagetool (found in the FSX SDK, it automatically flips the texture for you).


Bruce

I don't quite understand... what is the purpose of flipping the texture, and how does this relate to affecting the shininess/darkness?

I have only ever textured models from scratch (but not in FSX) so the texture usage here is all new and quite strange.

Edit: Just had a play with imagetool... I see what the flipping means now. Smiley

The result using that though is the same, the texture goes darker, not more/less shiny... very confusing.
 
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Reply #5 - Feb 12th, 2010 at 5:33pm

JoBee   Offline
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When editing the Alpha channel make sure you are not editing the RGB also.

Do this by verifying on the "Channels" palette that the RGB is not active.

cheers,
Joe
 

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Reply #6 - Feb 12th, 2010 at 5:54pm

LeeC   Offline
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JoBee wrote on Feb 12th, 2010 at 5:33pm:
When editing the Alpha channel make sure you are not editing the RGB also.

Do this by verifying on the "Channels" palette that the RGB is not active.

cheers,
Joe

Yeah, I'm ok on the editing side... I'm a games artist by profession. It's just that the texture usage here isn't your average games techniques.

Thanks for the heads up though.
 
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Reply #7 - Feb 13th, 2010 at 6:01am

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I've never experienced such a problem, Lee. I use CS3 and DXTBmp, try downloading DXTBmp and see if it still happens Questioning
 

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Reply #8 - Feb 13th, 2010 at 7:17am

LeeC   Offline
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Bah, it's that model... I tried some edits on another plane and it worked fine. At least I know what the problem is.

I guess this is the result of Microsoft using non-standard practices for transparency and reflectivity. Had they used the normal mapping channels (i.e. opacity and reflection), it would have standardised the process, and solved this Alpha problem. Seems an incredibly bizarre way of going about things really.

Thanks to everyone who has offered help.
 
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