PDA

View Full Version : Reflection Brightness Threshold w\ MIA


drossxyu
10-04-2007, 06:39 AM
I know there's the reflection cutoff, which is distance based, but is there a way to remove reflections of objects that are below a certain brightness? For example, I want my reflective object only to reflect my lamp geometry which has a super-bright (12 white) surface shader applied to it, but I don't want it to reflect the white table it's sitting on. Is this possible w\ the MIA material or is this something I would have to solve with multiple passes?

Also, Is there are a way to make something super-bright but actually have a color. I'm used to just setting the value of a shader to a value past one (which automatically makes it white), but could this then be tinted a very bright shade of blue or yellow?

-f

MasterZap
10-04-2007, 06:49 AM
I know there's the reflection cutoff, which is distance based, but is there a way to remove reflections of objects that are below a certain brightness? For example, I want my reflective object only to reflect my lamp geometry which has a super-bright (12 white) surface shader applied to it, but I don't want it to reflect the white table it's sitting on.

Note, though, that this is physically impossible. What is probably happening in the "real" world is that your surface is much less reflective, and your superbright object is much more superbright.

I.e. if you reduce your surface reflectivity to a tenth, and make your superbright object 10 times as bright, the superbright object will reflect the same, but your other objects would reflect less (which is quite possibly the real world effect you are trying to simulate; people easily over-estimate the reflectivity of surfaces when eyeball-matching them).

However, if you really want what you really are asking for, you could use the mip_rayswitch shader from the hidden bonus pack in Maya 2008 and switch out a different shader for your "white table" for reflection rays.



Also, Is there are a way to make something super-bright but actually have a color. I'm used to just setting the value of a shader to a value past one (which automatically makes it white), but could this then be tinted a very bright shade of blue or yellow?


You can still set it's color. It may "look" white in the color swatch, but it really "is" the color you set, with an overbright intensity.

/Z

drossxyu
10-04-2007, 12:54 PM
MasterZap to the rescue! What you said makes so much more sense than what I was trying to do. I changed my reflectivity to a .1 and got exactly what I wanted. Subtle, almost non-existant environment reflections, and nice bright reflections from the super-bright light source. Thanks so much!

-f

CGTalk Moderation
10-04-2007, 12:54 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.