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Did you know that an emitter set to a negative value will take away light from the scene to the same intensity as if it were set to a positive setting? Negative emitters in Maxwell work exactly as negative lights in other programs. It is a trick worth knowing and experimenting with. I don't believe it is mentioned in the manual.

I stumbled upon this sometime ago and was reminded about negative emitters by Lior Segal in an email. Thought I would bring it up here.

Cheers, Ron

WOW!!!

Ron this is so Awsome! I was looking for something to make more dramatic lighting for a while now!

I was eager to test this, but unfortunately this is not possible with the current Cinema4d Plugin

Sorry man I not understand you ...

It's also pollible to us with Multilight System ?

can you post a little sample image or scene ?

thank you.

I tried it in Studio now and it is not working there either.

What I tried so far:

- Changing watts and/or intensity to negative values [values always jump to 0]
- Setting luminance values to negative values (lumen,candela,lux & nit) [values always jump to 0]
- Rendering with multilight and entering a negative value in the faders (this always results with a black (i.e. value of 0) emitter)

Ron, please let us know how you did this!

BIG MISTAKE ON MY PART...I APOLOGIZE FOR THE MISPOST...I WAS WRONG ABOUT NEGATIVE EMITTERS...YOU CANNOT SET A NEGATIVE VALUE...

A ZERO WATT SETTING WILL WORK...

We could post this in the Wish List section, however I believe NL won'T do something like this as it is not physicly correct...or is it?

Black Holes absorb light too!

RonB wrote:an emitter set to a negative value will take away light from the scene to the same intensity as if it were set to a positive setting? Negative emitters in Maxwell work exactly as negative lights in other programs.

So in other programs that allow you to do this, if you have a GI lit scene and place such a negative emitter, the shadows it casts are brighter than the surrounding areas?
What's a typical scenario where one would want to use negative emitters? And what rendering packages do this?
Certainly an interesting concept.

johann, Lightwave will do it. All one has to do is set a light to a negative value and it will take illumination from the scene. For instance, you can place a point light to darken areas that you might not want illuminated, say in a dramatically lit character study.

I did a scene sometime back and as I remeber...I was experimenting with negative emitters in it. I posted this thread before researching it further. I should not have done that...again, my mistake...sorry.

O.K. and this works: An emitter with a zero watts setting will pull illumination from the scene. My mistake that I thought I remembered it possible to dial in a negative value...you cannot...but a zero watt emitter will darken the scene.

Here is the original post from 2006:

http://www.maxwellrender.com/forum/view ... light=mime

Here is an example:

Same lighting in each, the Sky Dome. You can see the edge of the emitter between the objects in the right image and the effect. Normally I would use Tom's method for hiding the emitter from the camera view.



[/img]

Can you replace the emitter with a black lambertian (RGB 0) ?
It would probably have the same effect.

Could you make the black lambertian object invisible to the camera and retain the effect?

"invisible to cam" in object panel won't do..?

Ron, the geometry is blocking the light flow because the objects hidden from camera still contribute to the scene. It's not about negative emission.

Btw, I'm sure you'll like this:
http://www.theatrecrafts.com/humour_darksuckers.html

Tom, Boy that article sucks!

O.K., so the plane is just blocking light?....Geez, now I feel like a real nit wit!
Sort of like I yelled, "Eureka!" and my pants fell down....