[Ernesto]

Ok, Here I am publishing the Fake HDRI Material that can be used to avoid the Colour Multilight current Bug
The material was based in Jason´s idea: http://www.maxwellrender.com/forum/view ... 15#p363541 and was tested succesfully and will not cause the Colour Multilight problem, and will act as a current HDRImage based material, this means that you will NOT be able to edit Colour in this material, but you will be able to do that for other emiters without problems while usig this material in the same scene.

Here you have the construction:


As you can see there are 3 layers with diferent opacity masks, and diferent emiter intensity.
This recreates the normal behaviour of an HDRImage based material, as can be seen bellow:



Anyway this material do NOT solve the unexpected rendering of invisible emiters.

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[Ernesto]

Conclusion:
Regarding the main topic, (as could be seen in the first post) the only available partial solution in Maxwell V2.7 is the following:

It is Not possible to use a layer Opacity mask to help reducing some of the noise (at least in the most transparent area) beacuse it will cause the other transparent materials to get visible again!
The problems will be that there is NO way to get rid of the heavy NOISE, therefore long rendering times, although Maxwell should not be calculating any refraction in there, and the Alpha, Materials, and Objects channels will be wrong, showing the suposedly transparent material as a solid object. Additionally tagging the volume with the conflictive material, as Hidden to Global Ilumination, will help a bit more to reduce noise, although all these tricks are not enopught they are what we have now.
All these (not minor) problems deserves, in my opinion, a patch for Maxwell 2.x users.
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[Ernesto]

Just for your records, here I am describing a bug, that might be related to the problem of this thread.
Perhaps this is the real cause for the previous unexpected behaviour.

Here I am publishing the construction of a simple invisible light for Maxwell V1.7

This material renders invisible without the need to tag the objetc as Hidden to Camera, nor Hidden to Secondary Rays.
I was able to use it for years without any inconvenient, but as soon as I upgraded to V2.7 it didn´t worked the same way.
In V2.7 it was necesary to tag the object as Hidden To Camera and Hidden to Secondary Rays to get the same result.
Perhaps this diference was causing the Malfunction when the suposedly hidden emiter gets unexpectedly visible when seen through a transparent object with certain emiter component.

Below I am posting 3 frames:
The upper frame was rendered in maxwell 1.7
The two cubes were assigned the previous material, and the transparent plane has a transparent emiter based in an HDRI
As you can see both cubes renders invisible as expected, although you could see the light on the plane.
I know this is the normal behabiour since I followed the intructions in your on line documentation:
http://support.nextlimit.com/display/tu ... e+Emitters



The second frame is the same scene rendered in V 2.7, but now the cubes render visible, although the material was constructed to be transparent, as explained in the online documentation.
In the third frame both cubes were taged as Hidden to camera and Hidden to Secondary Rays, but only the cube in front of the transparent plane did rendered invisible, meanwhile the other is still visible, but as soon as you remove the transparent plane, the second cube gets invisible again.

I hope this is easiest to fix, and that will solve the problem
Thanks in advance!

Ernesto

[Ernesto]

Here I am posting an image showing the diference between 1.7 and 2.7


In many aspects, the new image is superior in quality compared to the old version.
For instance the transparency of the image based emiters is much better, since in previous version those same materials were not really transparent but blocking the luminance of the others. You can see this in the following detail:

In general terms the colour lighting looks much more realistic, since in V1.7 all the saturated colour lights looked artificially burned.
The only problem, to which no solution was found, along this same thread, is the problem of the transparent emiters, as you can see in the upper comparison (orange arrows)
At the begining of this thread it was supposed that the problem was caused by the Image Based Transparent Emiters, as the title suggest, but the right title could be: Invisible Plain Emiters /sometimes visible, as noted in the test performed here: http://www.maxwellrender.com/forum/view ... 86#p363671
It does not look as a major bug, since it was working perfectly in previous version, but it is indeed a major obtacle for not only complex scenes, but very simple renderings as these: http://www.maxwellrender.com/forum/view ... 86#p363671
In my particular case, I have no solution, since each of the various explored possibilities, thanks to your help, introduced one or more issues, that made impossible to render without heavy noise, even at high sample levels and long rendering times, introducing refraction calculations where they shouldn´t be present.
I really hope this could be fixed in a patch for V2.7.
Thanks in advance
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