Alpha channel woes

[LeeC]

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. 

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

[Frequent Flyer]

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

[LeeC]

Just the darkness, the shininess remains the same.

[Bruce448]

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

[LeeC]

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.

The result using that though is the same, the texture goes darker, not more/less shiny... very confusing.

[JoBee]

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

[LeeC]

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.

[Frequent Flyer]

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

[LeeC]

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.