Interior lighting

[Alejandro Testa]

Hi guys, I am working in this project, using interior and exterior lighting, the main thing I dislike is the  sky white colour that come from outside. I can solve this issue saving as tiff with alpha channel and replace the sky in photoshop but when iI try this i lost the curtain translucency. Any suggestions? Thanks in advance.

[Roy Hirshkowitz]

How are you modeling the curtain material?  Try blurry reflection instead of translucency-- you should get more alpha channel.  Turn the transparency down a bit.  Make sure the curtain is tagged as "thin".

[akinlolu olugboji]

Something like this.

[Marc Chaumier]

Blurry reflection? Or blurry transparency?

[Roy Hirshkowitz]

Sorry-- transparency.

[Ros. Riha]

For masking, you can use material channel instead of the alpha - this way you will preserve curtain translucency

[Alejandro Testa]

Thanks guys. I will tag the curtain as thin. I am not sure but I think that the way to go is blurry transparency but it will be nice to have a small explanation between blurry reflection and blurry transparency and how to achieve this. (I know that is material option but what are the diference between both of them)

Ros can you give me a little example how to do this with material channel. I d´ont know how to use it.

Akin, I will look at your drawing...

 

Thanks again.

 

[Alejandro Testa]

Attached is "more or less" what I am looking for. In this case I save a tiff image with alpha channel and I put the background in PS, also I save a jpg image and I copy the translucency areas of the curtain to the tiff image.

[Peter Milner]

Seems to work okay for me.

Blinds are tagged as thin.

Material transpareny - 0.4

Material blurriness - 0.9

The only other thing you have to do in Pshop is blurr the background image behind the blinds.

[Alejandro Testa]

After 270 passes  I got this image, for me  is better than the previous one but I  still d´ont get the desire effect. Maybe something in glass definition? maybe something in the curtain material?. I also tried with Peter values satrting with a solid colour but there is something I am missing because I cam´t get Peter´s excellent effect. I also tried Akin material...

[Roy Hirshkowitz]

Get rid of translucency, use Blurry Reflection instead of, not in conjunction with.  You won't get any alpha channel with translucency set to 1.0.

You can test this as it's rendering by mousing over the curtain area.  The fourth color channel is the alpha channel.  Or right-click on the rendering and select Show Alpha Channel to visualize it better.

[Alejandro Testa]

Thanks Roy... I  will post the results.

 

[Alejandro Testa]

After 900 passes. In this case I turn off almost all the interior light, I left only sun, sky  and   10% indirect lighting on the ceiling