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neilp
04-19-2012, 06:16 AM
Hi all
Im rendering glass windows in a building and have trees image mapped to a poly with an alpha channel background as a reflection object. When I render the image the relections in the glass show a white background to the trees (the alpha background area) Can anyone explain how to get rid of this please

Neil

lardbros
04-19-2012, 06:29 AM
Hi all
Im rendering glass windows in a building and have trees image mapped to a poly with an alpha channel background as a reflection object. When I render the image the relections in the glass show a white background to the trees (the alpha background area) Can anyone explain how to get rid of this please

Neil

There could be a few things I think.

Make sure raytrace transparency is on.

You could try adding the alpha mapping into the object as a 'clip-map'. This is done under object properties, not the material (and is also saved with the scene, not the object... annoyingly).

If you render the trees on the plane by themselves, are they cut out correctly? But only wrong in the reflection? It doesn't make sense, but maybe if they're not rendering correctly by themselves, it could be that you don't have the alpha enabled within the 'Image Editor'?

Sorry, hope i'm not explaining anything obvious.

Tim

lardbros
04-19-2012, 06:32 AM
Just thought of something else... if you have an alpha on the opacity, but not got a similar map in your spec channel, or reflection channel (depending on if you have any spec of reflection), maybe it's that that is getting reflected in your glass?

Would be easier to see if you posted an image possibly? :D

neilp
04-19-2012, 06:59 AM
The alpha works fine and fits perfectly when i vew the object in front of the camera.

everything else you have mentioned is in order too.
I have the poly mapped with the tree texture in the colour channel and black and white image in the transparency channel.

I would like to figure this one out but for now the clip map way is giving me the result I need

Thanks Lardbros

D-Lab
04-19-2012, 07:07 AM
Hi,

The white part of your background poly could be the specular reflection of your surface (do you have some specularity ?), that's why clip map is a better solution in this case, with it you don't need to mask all the other channels.

Tchao

neilp
04-19-2012, 07:16 AM
all other channels are zero - I have no masks applied to the other channels though, am I missing something?

kopperdrake
04-19-2012, 07:25 AM
Use your transparency image in the Object Properties clip map channel instead of the object's surface properties. This should sort your problem out. Anything white in the image, if used as a clip map, will ensure that *nothing* creeps through of the image. If you need me to talk it through, skype me at the same username as I have on here and I can show you how.

Cheers :)