[deep__dive]

Hey there,

It ist still a Problem that Additive blending mode causes a lot of noise. After a recient test i conclude that the Additive Blending Mode isn't usable for interior renderings. But most examples, for one from Arroway, or even from Next Limit use the Additive Blending Mode. And i can't keep the quality of a material when i change them to the Normal Blending Mode. Does anyone have a good example witch shows how to convert a Additive Material to a Normal Blending material, and keep the quality?

[Mihai]

Please show these tests, would be helpful. Also upload the materials you used if possible.

[deep__dive]

Additive Blending Test:



https://dl.dropboxusercontent.com/u/100 ... ng-005.mxm

https://dl.dropboxusercontent.com/u/100 ... rroway.mxm

Normal Blending Test:



https://dl.dropboxusercontent.com/u/100586419/Boden.mxm

https://dl.dropboxusercontent.com/u/100 ... nd%202.mxm

[Mihai]

Would be great to have the maps and the scene as well for those mats. You can PM me a link if you don't want to share it publicly. Just on opening those MXM files though on the additive one the bump is a lot stronger. Also, what if you increase the reflectivity of the normal blended one to better match the additive one? I bet almost the same amount of noise will appear. What you are seeing are strong reflected caustics from the very reflective floor. Is it supposed to look wet?

[deep__dive]

It's going to the Drobbox. I'll send you the link when it's there. The Floor don't have to be wet. It's only one of a few tests to investigate how can i get a clean render so fast as possible. I think the wall causes also a lot of noise, but the reflectivity is much less.

[tom]

Basically, you are comparing inequal amount of reflectances. If you reduce reflectance or weights of your additive mxm OR increase the reflectance or weights of your normal mxm, they will finally produce the same amount of noise. Your additive layers mainly contribute to specular reflections while they remain very low and unnoticable as you directly click and turn "A" to "N". It doesn't mean you kept the material the same...

[Mihai]

Thanks for the scene, so as Tom mentioned as well, the increase in that noise is not simply because you switched that materials to additive - it's because it's a LOT more reflective compared to your other render. Here is a quick small rez test (to SL 16) of just switching the "Boden" material from Normal to Additive blending. As you can see there isn't more noise:



Some comments on the floor material. You are using the refl 0 texture also as the refl90 texture, a bit brighter version of it (this was said to be necessary in many cases), but in this case since the refl 0 texture is pretty dark, you want to lighten up a lot more the refl 90 texture. Otherwise you will end up with pretty metallic looking reflections and they will not look like laquered wood. Here is a screenshot comparing turning on / off the refl 90 texture. Perhaps the off version has too white reflections in which case you can add back the refl 90 texture, but brighten it up a lot more to avoid the metallic look.



Also I suggest to use that roughness texture, it can make the floor look much more interesting and varied. Without it, it will tend to make the roughness very even and so make it look like linoleum instead of wood. Here are some settings I used, just increased the brightness and contrast of the roughness texture:



Finally, the lighting setup in your scene is a bit strange. I know some people use the far away emitters to mimic the sun, but with V3 you have the sun radius to control the sharpness of the sun shadows so I'm wondering if this setup doesn't make your render pretty inefficient. Also you are using the IBL only for background and reflection, and a constant skydome for the illumination. Kind of takes away all the interesting lighting variations of the IBL and makes instead a flat lighting from the Skydome. Why not use the IBL for most of the lighting? Find one with a nice strong sun so you get sun light as well, and you can still use the IBL you already have in the background channel if you want. Will probably make the rendering more efficient...

[numerobis]

for me using high contrast IBL (sun) produces more noise than phys sky, especially for interiors - at least at the same SL. Is there anything you should avoid when using HDRIs?

[deep__dive]

Thanks a lot for your help!

it's good to know that additive Material do not cause noise, i have read it once in the forum that additive materials are like that. probably it was in the past like that and NL hace optimiced that. I was really comparing apple with oranges!

It was very interesting with the wood material, even if i know again that i know nothing about that, after years...

That "strange" lighting concept is the result of an endless search for a solution to get a clean render by using sky, ibl, and hdri maps. And i think there is now way to do that except you have a renderfarm or a loooot of time. When i only change the lightening to sky and reflection with hdri, the renderer needs twice the time, and i claim that when it reach SL 19 there ist still some noise (interior rendering). By the way, have a artificial sun helps also to have a good emitter balance. I really would like to work with the nice sun system of maxwell, but till now i don't have a practical solution for that. It would be interesting to see a good Light setup with hdri and sky from a professional like you, it could be that some changes are necessery in the sun parameter or in the ibl lightening to optimice that for interior renderings, some changes witch nowbody knows, an nowhere is anything to read about that, like the emitter balance...

[arch3d]

Additve method is harder to set up in my opinion. i got almost always white spots:P

[Mihai]

arch3d, have a look at this post:
http://www.maxwellrender.com/forum/view ... 35&t=41535

If you are still getting so many white spots with V3 and additive materials, please post it and tell us details.

I think it's been mentioned a few times on this forum regarding lighting setups that the slowest kind of lighting you get is when you mix emitters (regular emitters + IBl, or regular emitters + Phy Sky). This post in the docs demonstrate this pretty well:

http://support.nextlimit.com/display/tu ... or+renders

Read especially the "First Scenario" and in that the "Render time - using Multilight as a "Noise control" paragraph. Essentially you have the option to "hide" the noise by turning down the influence of the Physical Sky (or IBL if you used that for environment lighting) using the ML sliders. The Sky will still give some influence to the lighting in the scene and make it less grey and flat looking, compared to using emitters alone by the windows.

Also placing the emitters inside the window frames like that makes it more efficient, than placing them outside the building surrounding it.

Multilight is a great way to also quickly see which emitters are giving you the most noise. Just solo each one, one by one and you'll see. Sometimes it can be pretty dramatic - most are almost noisefree, while one is noisy as hell. Then you know you need to do something with that emitter. Maybe it's in a awkard position where very few light rays shot from the emitter actually reach the camera (think emitter behind an almost closed door and this is the only illumination in the scene).

[deep__dive]

Congratulation NL! V3 is really optimiced. This Picture ist Rendered with Sky and Hdri, without emmitterplanes (3 emitters for night scene), and of course it needs more time to render than a scene with emmiterplanes, but it's possible to reach a almost clean picture a SL 19 without any withe spots!

https://dl.dropboxusercontent.com/u/100 ... htning.png

so i will try to work again with sky and hdri. it would be interesting to see how it would be with additive materials and sky / hdri lightening... maybee when i get some time a make another test.

[arch3d]

I think it's been mentioned a few times on this forum regarding lighting setups that the slowest kind of lighting you get is when you mix emitters (regular emitters + IBl, or regular emitters + Phy Sky). This post in the docs demonstrate this pretty well:

http://support.nextlimit.com/display/tu ... or+renders

Read especially the "First Scenario" and in that the "Render time - using Multilight as a "Noise control" paragraph. Essentially you have the option to "hide" the noise by turning down the influence of the Physical Sky (or IBL if you used that for environment lighting) using the ML sliders. The Sky will still give some influence to the lighting in the scene and make it less grey and flat looking, compared to using emitters alone by the windows.

Mihai i read it many times trust me:)
I think best effect is when you mix IBL+Emitters
Chapter "Sky with Sun" works only in simple situations - no object in sun square
And again some questions:)
In your opinion (regarding noise/render speed) better way is keep real emitters power (45W,60W,100W) and play with camera settings or tweak lights to unrealistic values (5000W,10000W etc)?
And second one:)
If i got e.g. 10 light with the same intensity. Better way is keep all of them as separate meshes or merge them into one object?
Thx

[Mihai]

Second question, doesn't matter in terms of render speed or noise.

For the first question, this again matters if you mix regular emitters with a light source much more powerful such as the sun. It's been said that in these cases to "even out" the optimisations Maxwell tries to make, to give your emitters very high values, and then lower them using ML. But I haven't tried this yet personally. Give it a go and post the results if you can.

If your scene only has emitters then best is to stick to real world values, and for the camera also. This just makes the whole process more predictable, and also can avoid some ugly precision errors when you are using millions of lumens emitters.