[PCONCA]

And What´s the inconvenience to use this configuration Mihai?:



Excuse my ignorance....

[Mihai]

Try using the simball scene for testing, and recreate first this material in your above renders, then use additive blending, with the shiny bsdf placed in an additive layer above the red diffuse. It will become clear to you then

But btw, you should never use such a high ND with Force Fresnel. There isn't any shiny coating that has such a high ND. Stick to around 1.3-1.6 for the ND of the shiny bsdf, if you use force fresnel.

[tom]

When you have 2 BSDF @ equal layer weights in a Layer, it means they are weighted 50% each. If you have 3 BSDF, they are 33.3% each.... very simple.
So you are attempting to render a full red shiny ball and you set the reflectance of diffuse BSDF to 255,0,0. Now, check the following formula:
Resulting Red = Weight of BSDF * Input Red
This means your red is going to be halved due to the normalized layer weight and it will come out as 127,0,0.
If you have placed the specular BSDF in a separate layer above and set it to Additive, the diffuse red in the base wouldn't be affected. Makes sense?

[photomg1]

Try using the simball scene for testing, and recreate first this material in your above renders, then use additive blending, with the shiny bsdf placed in an additive layer above the red diffuse. It will become clear to you then

But btw, you should never use such a high ND with Force Fresnel. There isn't any shiny coating that has such a high ND. Stick to around 1.3-1.6 for the ND of the shiny bsdf, if you use force fresnel.

will give that a go Mihai ! it is kind of strange/confusing that the example yellow plastic on the simball scene is made just blending two bsdfs in normal mode if that is incorrect (maybe that needs an update ?)

one with an nd of 20 the other 4( I suppose due to force fresnel not being checked)

[dariolanza]

At the time that step-by-step guide to materials were written (v2 times) going Normal were the best and safer way to go, as Additives could cause problems and frustration on new users. This is why Normals are still more recommendable for new users.

Now that Additives don't present numerical errors, you can turn them Additive if you prefer (keeping an eye on not to bright your material too much).

By the way, the link you looked for was in the Knowledgebase>Materials>Material examples-How to section:

http://support.nextlimit.com/display/kn ... s+-+How+To

Cheers

Dario Lanza

[photomg1]

doh!

[numerobis]

This is interesting. Looking at this comparison it seems that additive is producing less noise now.

[photomg1]

I wouldn't make that judgement based on these Numerobis .I just eyeballed noise levels as it wouldn't let me export to a full render, these are just screen grabs from within studio.

[Mihai]

I don't know how you did that conversion because here I can see a pretty big difference. How did you sample the yellow to recreate the additive material? You should just copy the RGB values of the yellow BSDF in the old material.

[photomg1]

Hang on a minute , I might have made an error .. oops

I better double check..

could you post a screen grab of what I should be seeing mihai?

edit :yes I did make an error massive apologies , just letting it render some more.

[photomg1]

I take it this is what I should have been seeing Mihai ? It does look more like a coating extreme edges have a much brighter fresnel , and the bottom lambert material has more form/shape in terms of graduations as well. That seems to be the best way I can verbally describe it anyway in layman's terms .

Please correct me if I'm wrong again Mihai ( big thanks for your help in me understanding this btw ).

It does seem that it would need much more time to clear the noise on it though

[PCONCA]

It looks reasonable and is coincident with your opinions...

https://www.youtube.com/watch?v=sof2gfMQXwc

You agree? tomorrow I´ll do probes to see times and noise... I´ll share the results but seems logical...

[eric nixon]

The additives are working perfectly correct as long as one of the components is not SSS or dielectrics and that's all. Further discussions are urban legends.

Thanks for saying that. Armed with your conviction, I ran some more tests using an additive spec at 100%

The problems of glowing noisy recesses, glowing fresnel edges, and slow renders seem to go away IF the R90 in the spec is reduced, I found that 235 was a good max level. which means that Force-fresnel can't be used. It also means that ND should be increased to around 3 to compensate, and the R0 set to 0, to achieve a decent fresnel effect. For the diffuse I used a very high roughness of 99 to mimic the absent sss, and r90/r0 were set to 245.

There is some noise still at sl21 due to the brightness of the material, but it will clear. (this is the worst case scenario afterall)



Anyway these are my conclusions after 1hr of testing, If someone from NL can upload a better example of a white laquered material, That would be helpful for everyone.

[eric nixon]

This one is less noisy, and 30%quicker, and a bit more glossy. Additive at 70% with ND-4, diffuse rough @ 98.



sl21 rendertime 35 mins 12core 3.6 ghz

[Mihai]

I found that 235 was a good max level. which means that Force-fresnel can't be used. It also means that ND should be increased to around 3 to compensate, and the R0 set to 0, to achieve a decent fresnel effect.

I'm again not too sure what that means and how you arrive at those conclusions. An ND of 3 won't make a very realistic fresnel effect I think, no matter what else you fiddle with.

What I like to do is simply start with a realistic ND of say 1.4 and leave the refl90 of the shiny bsdf at full 255.

If you have a too high ND for the shiny BSDF (as I think photomg1 did in his additive test), then of course you get a much too strong reflective "coating", more noise, and practically no fresnel effect (meaning your material will be equally reflective across all viewing angles).

So try to keep the ND of this reflective layer in normal values, and I see no reason why force fresnel shouldn't be on in this case. You can in fact simply forget about the refl0-90 colors, because with a low roughness, the reflectiveness of the surface will be dictated by the ND alone.

photomg1, see what Tom wrote because it's pretty clear really what additive does. It allows first of all to show the diffuse color that you have chosen because it isn't blending it at all with any other BSDF you may have in the same layer (normal blending). So the first and most important thing is your diffuse base color will remain as vivid as you set it. And the second behavior is that your shiny "topcoat" will not get dull, as would happen if it has to fight with the percentage blending of the diffuse BSDF in the case of normal blending.