Help with alpa channel

[Archigraphica]

More info please? Which version? what platform?

[brehaut]

Version 9.5 win xp

[Archigraphica]

I tried setting up a similar scene with an image map background and a 2D tree image with an alpha channel. It worked fine. Tried it every way I could think of and couldn't reproduce your results. Even played with a compositing tag on the background with no luck. What are your render settings under Options? ray, reflection, shadow depth?

I'm having a different kind of Alpha problem but I'm nothing you're getting. Out of curiosity I upload the sample scene to my web site. Why don't you download it and see if it screws up or works. Maybe it's something with the textures or somehow the file itself.

www.archigraphica.com/alphatest.zip

Let us know if it works?

[ODoul]

Looking at the image, it's pretty clear that it has something to do with the sky. Give us more details please.

[brehaut]

for the sky i have use cinema standard sky object with material using luminace channel set to 100

Sorry for the lack of information i just are not smart enought to no what info you need

http://i7.photobucket.com/albums/y270/brehaut/alparendersettings.jpg

[rikke]

Don't know if newer versions of cinema have fixed this, but in my experience: alpha + GI + sky= a big no-no
You could avoid it by having 'something' between your alpha plane and the sky, or by using a big sphere for background.
Sorry for the misinformation if there IS a solution, but this situation kept me busy for hours in the past, and never found a decent answer to it...

[macling]

This alpha channel+global illumination via sky object bug is a very old one.
Only solution I know is using a big sphere instead of a sky object.

[jph]

This alpha channel+global illumination via sky object bug is a very old one.
Only solution I know is using a big sphere instead of a sky object.

jesus! why didn´t I think of that before!, would have saved me heaps of time....

later Jan

[rikke]

jesus! why didn´t I think of that before!, would have saved me heaps of time....



Don't get your hopes up, a sphere spreads the GI calculation in a whole other way than a sky object. You'll have more artefacts and longer render times. Especially for outdoor scenes

[Archigraphica]

I can't reproduce the problem. I've had similar image related problems in the past (png files) where my quicktime installation got corrupt and I had to uninstall the old one and install an updated version. Have you tried that?

[TimC]

in 9.5 compositing tag you can include / exclude objects for transparency. I think you need to put a compositing tag on the sky object and exclude the alpha mapped planes.

cheers
Tim

[brehaut]

Thank you people for all the help , your input got me thinking and i put compasition tag in and checkewd not seen by rays and this fixed it, i hope it want cause any other problems that i dont no about, but it seems ok.

[brehaut]

That was a bad idea, now there are no shadows

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