Strange "glow" around opacity maps

[BBullo]

I'm having trouble getting a good texture using Xfrog and Vray.
I think its a simple opacity map issue.
The material I'm using is a Vray Material and has an image in the diffuse slot with an image for the opacity in the opacity map slot.

Here is the first attempt-notice the white edges of the leaf.


The next one i tried constricting the opacity channel to cut off the white border possibly comming from the diff image.- the glow was still there.

Next, I tried applying a black image file to the diff slot. -Still has the glow around it.


Next, I tried un-checking the image in the diff slot and just used a color instead. No Glow!!




Then I tried applying a completly different image BMP file type but the glow came back.


Any ideas? I really need to get it working with an image in the diff rather than a solid color.

[percydaman]

try settings the texture map to blur 0.0 and filtering: none and see if that helps. usually helps me.

[vlado]

What image format are the textures in? Have you tried playing with the "Premultiplied alpha" option of the bitmap textures?

Best regards,
Vlado

[BBullo]

Percy The Blur set to 0.01 made a big diffrence. As for no filter are you talking about turning the AA filter option off or something on the material level?

Vlado, "Premultiplied alpha" is something i've never messed with. I'm looking into it right now. It was already checked in my material by default.
It looks like the only control I have over this is if I'm saving the image file to output to .TGA. Are talking about controlling this on the map level from Photoshop?

[instinct]

just a quick rundown of boring "premutliplying" theory.

Premultiplying basically means that the background colour is included in the foreground colour. So lets assume you got black as background for example and a green layer on top that has an antialiased alphachannel. Now when saving premultiplied the actual colour blended with black is saved + the alpha. without premultplied only the colour in the green layer (plain green) and the alpha are saved. So if you save premultiplied you basically have to "demultiply" in order to get rid of the included background colour, or you´ll get strange artifacts around partially transparent bitmaps.

The glow seen here looks like an image with alpha that is premultiplied with white, so you might wanna look into that.

The fact that blurring less helped could be because of the "premultiply border" beeing more evident when blurred.

Thorsten

P.S. sorry for the bad english...am not a native speaker

[percydaman]

Percy The Blur set to 0.01 made a big diffrence. As for no filter are you talking about turning the AA filter option off or something on the material level?

Vlado, "Premultiplied alpha" is something i've never messed with. I'm looking into it right now. It was already checked in my material by default.
It looks like the only control I have over this is if I'm saving the image file to output to .TGA. Are talking about controlling this on the map level from Photoshop?

The filtering method is found in the material rollout. Youve got pyramid, summed area and none. Try none.

[Candelero]

Good explanation instinct

@ BBullo,
what percy said, it is in the - Bitmap parameters - the first on top left...
it says << Filtering >>

[BBullo]

DOH!!!!...I see it.

As far as the pre multiply goes, I opened the origional PNG file in Photoshop, modified it and saved out as a bmp. I don't know if pre-multiplying would carry over from the origional file or not.

The blurring ang filtering worked like a charm. thanks Percy.