How do you work with emitters?

wildbillnash

I'm trying to make some things glow and just can't get the hang of it.  I have i13 Future Visions Envinment and Poses with 5 emitters located under shaders>emissives.  I click on the surface to use the emitter on and it does change to the color of the emitter (with the texture tab chosen).  But it doesn't really glow.  Also, when I change to Iray view it's no longer that color.  Is there something else I'm supposed to adjust?

andya_b341b7c5f5

Checking the obvious first.  Select your object in the Scene pane, then select the surface you want to emit in the Surfaces pane.  Now in the Surfaces pane, look for the Emission Color and make sure it's not black, or some other color with a low value - suggest you start with full white.  Next, look for the Luminance Units: the default is cd/m^2 (candela per meter squared) which are feeble; choose kcd/m^2, or W if you prefer Watts.  Now bump up the Luminance value and the surface should glow - how much you need will obviously depend on the brightness of the environment generally, you might need some high numbers (tens of thousands).  Set the Emission Temperature to 6500 (white) initially so the light emitted is not colored, you can mess with that once you have a glow going.

wildbillnash

????  Okay...I catch some of what you said.  Can you mention where I can find some of those settiings?

wildbillnash

Okay, played with it some and see what you meant.  Thank you for the info. The emission color is correct, red.  The temp is set at 100,000 (whatever that means).  I found the Luminance Efficacy slider and raised it to 10,000, units set at W.  The Luminance slider is at 1638.  Not sure which increases the glow, the Luminance slider or the Luminance Efficacy slider.  Going to have to play around some more.  Thanks again for the info.

andya_b341b7c5f5

You will find that if the Emission Color is red then the Emission Temperature will have little effect.  With an Emission Color set to white, a temperature of 1000 will give you red, orange or yellow light depending on how much light is being emitted - from low amounts to high amounts (not sure how physically accurate that is).  A temperature of 10000 will give a bluish-white light at lower levels of light, and will become whiter as the amount of light emitted increases.

wildbillnash

Interesting.  I'll have to experiment with it.  I used the emitters that came with the Future Visions add-on thinking it would do the job.  The emitters and settings that came with Daz i have no idea how they work, yet.

Thanks again.

SpottedKitty

About the Emission Temperature setting: it's essentially a colour tint applied to whatever colour and/or texture you have applied to the light itself. To get technical, the colour is "Black Body Radiation" — if something gets hot enough, it glows. There's a chart here that shows the relation between temperature (in degrees Kelvin) and colour, and a table here that gives example temperature settings for different lighting types, from an orange match flame to white outdoor daylight; this is the default setting of 6500°K for a newly created Iray light.

Boosting it waytheheckupthere to 100,000°K probably results in an unnatural-looking render, that's the sort of temperature you'll find halfway to the centre of the sun...