Is Alpha = Transparency possible?

[Chris]

are you talking about the background being an alpha when rendering, or do you mean to have a opacity map on an object, so that portions of the object are transparent?

[polygone]

Yeah the backgroud of the star transparent. Will it display in the modeling window too?

[Chris]

what star? Your confusing me... :) Ok, if you want to map a star onto an object, & have it partially transparent. You would put a black & white image of the star into the materials opacity channel (you may have already got that far) you can show the object partially transparent like that in the viewport. Just click on the 'show map in viewport' button at the top of your material's settings. If it doesnt work, its probably an issue with your video card, or the drivers you are using. If you do have problems, try using one of the other video modes

[polygone]

I'm sorry about that star comment...that was a different post :D

Anyway...Sounds right, and that way works.

Now, I'd like to use the same image for the diffuse channel and the Opacity channel. I will use the RGB channels of the image for my Diffuse and I will use the Alpha channel for my Opacity. When I set it up this way, it renders right, and it looks right in the material Editor, but it does not show the transparency in the modeling window. It shows up as a solid material.

Any suggestions?

[Chris]

That should be easy enough. Make sure the map in the opacity channel is unique (ie, its not an instance of the diffuse map). Then in the bitmap settings on the left hand side, there should be a setting for 'mono channel output'. Change this from RGB intensity, to Alpha. That should do it! :)

[polygone]

Hey thanks Chris. What video card and OS do you use? It seems that Max5 won't display it for me in the modeling window. I'm using WinXP and a GeForce4.

[Chris]

The computers I use are all Windows2000, with Geforce2 cards. I you think its a video card issue, try changing to the sofware renderer in the preferences & restart. Are you using the latest detonator drivers? What type of image file are you using for the map? (also make sure you have the 'show map in viewport' activated at the top level of the material, not at the local map level)

[suck]

make sure you have viewport transparency set to "best" in the viewport configuration panel. its a new "feature" in max5 and it defaults to "simple" which doesnt support alpha maps, only object transparency.

[Chris]

Just found that out myself... Apparently each time you open Max it will revert back to 'simple' too, but they are planning on fixing this in an update. :shrug:

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