Emissions mask map or something like that?(Solved!)

McGyver

I've been experimenting with Iray and the the various functions of the shaders and I was wondering if there is a way to mask portions of a image or map used in the emissions channel... Some programs that use emission maps also have a node or place to plug in something like a specular map or alpha mask (using grayscale) so that you can limit or stop certain areas of the image you are using from emitting glow... One example of a place where you'd want something like that to work, would be an image of a window... You'd want the glass to glow, but the mullions and frame not to, so they would be masked in that node...
I'm probably not using the right terms, but I think that is close to what I was trying to describe.
I was able to light up the windows in a building test model I made, but I could not find a way doing what I described above.
Anyone know if that feature exists in Iray?
Thanks!

Richard Haseltine

Doesn't black in the Emissive colour work?

AndyS

Hi,

isn't your windowframe a seperate node with its own surface textures?
In case not, you can create a texture map with black frame for your emittive window and apply it to the Emission Color parameter.

vwrangler

I may be missing something, but for Iray, I think a simple transparency mask in the Cutout Opacity channel should work. The parts where you want light to show would be white, and the parts where you want light blocked would be black. I think that's how that works, anyway. That's what the mask used for the Cornea surface looks like, and where it goes.

McGyver

@:
Richard Haseltine: I thought black shuts off all emissions?

smftrsd72: The test model does not actually have a mullion or frame detail (but a different test shape did), it's a single sheet of glass, like an office window... But it was just a test model... Some programs that use emission maps have a place to plug in or add a node or channel that allows for a grayscale map to assign different glow values to the emissive map... Sort of like a displacement map works... Except black is no light, white is full value and the grayscale whatever lies between.
I'm trying to avoid having to have different geometry for areas that I'd like to have a glow... I want to mask off the glow only, not make the masked of area invisible.

vwrangler: When I used a transparency map in the cut out channel, it cuts out the area I want to glow... In the example of the window, the frame and mullion were gone (invisible) and the "glass" and details behind (blinds and interior image) remained, but did have a nice glow.

Richard Haseltine

lordvicore said:

@:
Richard Haseltine: I thought black shuts off all emissions?

Isn't that what you want? You have a map that's black for the non-emissive areas and white for the emissive (or tint it, though you have other controls that will do that).

McGyver

I'm probably not explaining it well, or I'm not understanding what you mean...
In the picture below, I first tried to apply the texture to a cube primative, and then find somewhere to apply the mask... it didn't work, like I thought... the effect below is what I wanted, but it was achived by recessing the window area and mapping that separately, adding the window image into the emission channel... no mask is needed, but what I really want to do is not have a separate material zone... just mask off the windows so they glow, but the other areas are like the diffuse map.

Excuse the stupid spelling mistakes in the image

Richard Haseltine

Apply the Emission Mask texture to Emission Colour, and set the base colour for that property to white (so the actual colours used will be the map's colours). Set the temperature and so on as desired for the light. Does that not work? It seems to for me.

McGyver

Thank you!
That was half of what I needed! But it really helped me get to the next part...
I got image masking, but no window detail...
I messed around with it a bit and noticed luminance had the ability to take an image map...
Apparently I needed to plug the same image that I used in the diffuse channel into the luminance channel!...
I'm rendering it now, I'll post an image to show what I mean, when it's done.

Weeeeeehoooo!

McGyver

-The first image is just that basic cube-like model in the viewport.

-The second image is the model just using the mask map in the Emission channel... Like Richard said, The color must be set to white... I stupidly was either adding color or leaving it black before, which is why the mask was not working at all.

-The Third image is with Mask Map (in Emission channel) and the same image that was used in the Diffuse channel (In Iray- "Base Color" channel) plugged into the Luminance channel as well.
Now you can see the details in the window... office interior, blinds... etc...

-The fourth image is in case anyone else is trying to figure out what the hell I'm trying to show, but I'm explaining it badly...

Its not perect, but now I can mess around with settings until I get something I like!

Thanks to everyone who replied!