Help Me Understand Emission Plane Controls

[AxiomCG]

Adjusting the power of an emission plane is one of the most strait forward and simple things to do in any render engine that has them. In indigo however, this basic function seems to be hidden somewhere. None of the sliders under the emission section--labeled "Base Emission" and "Emission"--seem to have any effect on the actual brightness of an emission plane.

As a result every render is blown out, as you would expect the render to be if you were to turn emissions up to maximum.

I have come to understand that there is a parameter somewhere that governs the actual brightness of the plane, and (at least I think) these other sliders function as a multiplier. I however, for the life of me, cannot figure out how to change the emission strength of one of these planes, nor have I been able to track down a clear example of how to do so on the internet.


Could someone please clearly outline the process of changing the illumination strength of a single square emission plane.



Edit: For The Devs
To the Indigo devs, this may be the most beautiful and realistic rendering engine in the world. You may want to consider adding a simple, universal emission control slider. Day one with a new software is always confusing, but when it is so hard to change the parameters of something as basic as an emission plane it can be a major turn off. It can make people anticipate future pitfalls, as they may come to expect counter intuitive solutions to even more complex problems as they arise.

This really should be a very simple adjust-a-single-slider type thing, in clear view and in the materials section. At day one I have encountered two sliders with 5 parameters each with a total of 22 sliders that seem to only change light color, and turn them on and off. But no control for intensity.

[CTZn]

Hi AxiomCG,

you might have been deceived by the tonemapping method: the Reinhard tonemapping will scale with emission powers in order to produce the same luminosity max output.

Change the tonemapping method to Camera, this will emulate real films responses. The default film values are normally what you want to set light powers against.

[AxiomCG]

Under emissions, if I set it to "black body emission" and then set the Temp to 4,500 and the Gain to .0002, I can then play with the camera tone mapping settings and get an image that is not so blown out. Thank you.



My next question is: is the gain always meant to be set to such extremely low decimal points or I am doing something wrong? Also, why is it that even when I set all of the RGB sliders to maximum, and then all of the camera tone mapping sliders to maximum... the screen is black. Is camera tone mapping only meant to be used with black body emissions and nothing else?





Second QuestionL

When emissions is set to RGB and Base Emissions is set to Black body I can change the color of the light without altering the intensity of the black body. But setting both Base Emission and Emission to black body turns the screen black even at max settings.

In fact, no other combination of sliders seems to be generating any light at all when I am in the Camera tone mapping mode. Even in max settings. Is this working as intended?



I would appreciate it if you could help me understand all of this in better detail. I am not grasping the purpose of the two emission sliders and how they work in concert.

[CTZn]

My next question is: is the gain always meant to be set to such extremely low decimal points or I am doing something wrong? Also, why is it that even when I set all of the RGB sliders to maximum, and then all of the camera tone mapping sliders to maximum... the screen is black. Is camera tone mapping only meant to be used with black body emissions and nothing else?

It sounds like you are not using Emission Scale wich would force the output power to a custom value. In this case blackbodies are using their own gain system that is very strong; it is normal indeed to use such small values.

In the other hand, non-blackbody spectra (may) use a default of watts per square meter for power, wich even at 1 1 1 is extremely low. Try higher values (super-colors), a different spectrum type or use Emission Scale.

Second QuestionL

When emissions is set to RGB and Base Emissions is set to Black body I can change the color of the light without altering the intensity of the black body. But setting both Base Emission and Emission to black body turns the screen black even at max settings.

In fact, no other combination of sliders seems to be generating any light at all when I am in the Camera tone mapping mode. Even in max settings. Is this working as intended?

The blackbody spectrum type is not meant to be used as Emission. It is specifically designed for Base Emission. Emission is a mere multiplier to the Base Emission power.

What exporter are you using ?

[CTZn]

tell you what, emission can be considered optional with a blackbody as base emission; use then the temperature to shift color tones (and Emission Scale if you are more comfortable with the values). That is the most natural and basic lighting scheme.

[AxiomCG]

Thank you for your time in answering my questions. It is very much appreciated. I am using the Indigo to blender exporter but I am basically setting everything up in Indigo itself atm. I merely export the geometry and camera position.



I have seen emission scale referred to in other threads that I have researched. However the only emission scale that I can find is in the background settings and it seems to only effect an HDRI map. If you can tell me where this features is located for emission planes as well it will probably clear everything up for me. Again thank you for your replies.



I have not even been successful in finding this information inside of the Indigo documentation.

[CTZn]

In indigo these settings belong to the Object type (as opposed to Mesh type); that's because some emission units are depending on the model's square surface.

You are welcome, I was lucky to help.

[FakeShamus]

...I have seen emission scale referred to in other threads that I have researched. However the only emission scale that I can find is in the background settings and it seems to only effect an HDRI map. If you can tell me where this features is located for emission planes as well it will probably clear everything up for me.

In Blendigo you would assign a material to your emitting planes and adjust the emission scale under the emission properties of that material. I agree that the base emission and emission properties in Indigo itself are not very intuitive. But in Indigo you control the emission scale as a property of the object you want to use as an emitter, not the object's material settings. If you select the emitter object from your list of scene elements in indigo you can adjust the emission scale there.

Edit: ...beat me to it, I didn't see CTZn's reply

[AxiomCG]

Ok thank you very much. Now it is working

They really should dedicate an entire page to just this aspect of Indigo in the documentation. It is just so utterly different then anything else out there. Thanks again. I am sure that I will be posting here again in the not to distant future.