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JustLearning
12-31-2008, 10:03 PM
Working with a window in a winter scene and trying to get a foggy effect directly on the window. I have a separate plane for the fog. I made a quick Grayscale JPG in photoshop representing the fog. Alpha as Luminance checked ON

Things appear to work correctly accept the fog is appearing black. The Blinn shader has only the transparency map plugged into the transparency node, the color of the blinn is straight white so whatever isnt transparent should be totally white. So why is the plane showing dark instead of white????

Here's a region render of the window with shader network and shader settings and transparency map

http://www.danielmatuk.com/render/fog1_dan.jpg
http://www.danielmatuk.com/render/fog_dan.jpg
http://www.danielmatuk.com/render/shader_dan.jpg
http://www.danielmatuk.com/render/shader1_dan.jpg
pap87
01-01-2009, 03:02 AM
Two things I can think of.

1) Invert the map, white is transparent and black is opaque.

2) I think the connection should be .outAlpha to .transparency.
djx
01-01-2009, 01:44 PM
What is your lighting? Maybe it looks dark because there is no light hitting this surface. You could try adding that map to incandescence as well, to fake it.

-- David
JustLearning
01-01-2009, 07:24 PM
pap87 - was just a black and white jpg, there was no alpha channel, and i tried your suggestion of inverting the map, just put the black on the inside. thanks though

djx - once again your insight has put me on the right track. plugging in the map to incand. has boosted the white present in the map and with a bit more blurring in photoshop is def getting the effect i wanted.

also using the fog map on a plane pulled away from a separate plane that is the actual glass of the window, boosting the reflection of the window has actually helped as well.

of course in the end this def appears like an effect that can be achieved in post, but always looking to get things right in maya first