Making dirt in the fresnel/reflection

[Fabian-Eshloraque]

Hi Guys,

I found an fast easy way to add some realistic detail in the fresnel reflection of objects with reflection. You can also mix it with a reflection map going to the input amount fresnel or the input reflection blurring. The main reason is to simulate the texture of a varnish. Cause varnish is NEVER perfect so it means that the reflection/fresnel needs texture.

So see the screengrab and let me know if its works.

Grtz!

Fabian

[Fabian-Eshloraque]

Here's an example with just a procedural shader plugged in on a black ball in a grey background. The nodes and shader are also attached.

Grtz!

[djwaterman]

I don't know if I made the set up better, you tell me. My thinking was to keep the diffuse exactly the reverse of what is going into the reflection.

[Fabian-Eshloraque]

Hallo Djwaterman,

I will test. I think the way it was setup-ed that first part was to limit the value of the light emitting. So my guess is that your adjustment should render a bit faster. Maybe Janusz knows more. I will do some testing when I have a bit of time.

Thx and Grtz!

Fabian

[Janusz Biela]

I am not sure is correct inject something inside diffuse system (as You did in Clamp Node)
Last my updates about Fresnel system is that (I use this now in all surfaces)

You can notice a couple new thinks:
- Fresnel is from Lightwave (so I do not stick with third part software - in this case DP Kit...also good for network rendering because everything happen inside Lightwave so 100% compatibility. Also I had some problems with DP Fresnel - it was topic about it - I think problem in Kray with compatibility)
- I mix reflection map (in this case Crumple procedural - but it can by anything) with Fresnel - so in output I get reflection map connected with Fresnel effect. Map for mixing must have ALWAYS maximum acceptable luma level! - this is important. I do not want change too strong Fresnel physics.
- after multiply You can notice Color Tool ...and this is my small update also. The Fresnel effect seems for me too strong on the edges and too weak in center (Yes! It doesn`t mean it is correct in render because is done according to physics!) so I reduce this effect by Color Tool all the time in the same way for all Nodes + I see effect of connection which is very important. This level give me the best results (small correction tool for Fresnel effect):

sc_015.png (3.91 KiB) Viewed 9403 times

This part never change! Always is the same for all surfaces:

I slowly add one more update. As we know dark and bright surfaces has different Albedo so I think for very bright surfaces system of diffuse should be as images before but for dark surfaces Subtract should go down to minimum 0.6. I notice dark surfaces with reflections are not that dark as should be. Last time for dark ceramic and similar I change Subtract to 0.6.

Color Tool is the most important Node from all. By this you change everything:
- hue (for example loading brick texture I changed color. Can be also contrast/brightness ) This is important! Because almost all textures need to be TWEAK before! Most of them has bad gamma, colors, contrast.
- reflection map - in this case I inverted map and rise up brightness
So One Node, One texture and 10 sec of tweaking! - nobody can be faster - it save a lot of time.
Sometimes we need different textures for bump/reflection/diffuse - for example good floor surface.

fresnel.srf

(47.47 KiB) Downloaded 216 times

basic.srf

(48.82 KiB) Downloaded 203 times

[Janusz Biela]

Next small update from my collection: Bump DropOff (I think is easier solution but I stick with this one)

It gives me better AA effect on the objects edges or in situation when camera watch surface with angle close 90. Reduce moire effect also. It must be use for cloth materials!

basic_bump_dropoff.srf

(50.24 KiB) Downloaded 215 times

Here we see:

Front camera view - bump 400%
Camera view close 90 degree - bump 0%

It is easy to control and very universal

[djwaterman]

Can I ask what will seem like a dumb question? What is doing the job of reflection blur in these set ups?

[Janusz Biela]

Can I ask what will seem like a dumb question? What is doing the job of reflection blur in these set ups?

Actually this is the most intelligent question ever
If you mention this

the answer is only one: the most important part in Nodes.
Here examples from photos:

It gives differences in fracture of wood. As we know many materials (almost all) has not ideal blur on whole surface, especially wood. Some parts are more blurred some less. Putting standard blur give artificially (I suggest forget traditional way) so this is next physical simulation.
Invert in Node also is important because reflection blur has inverted reflection value (not always).
White colour means stronger blur, completely white surface after Color Tool means 100% blur. Why after is Color Tool Node to tweak values by contrast/brightens - is depends what user wants achieve in render.

It needs a bit training but believe me after that, whole setup of one surface (bump, Fresnel, reflection map, reflection blur, colour texture, etc) takes 10-15 sec! for example after preview render when we need achieve our designed result.

Without this part of Node you will never achieve good result, is just impossible to do it in standard LW setting.
Anyway I suggest again use only Nodes. There is no way for good surfacing , using old system is waste time - in Nodes surface can be made faster and better.
...and I remind: All good renders from Maxwell, V-ray, etc, are done through Nodes.

[Fabian-Eshloraque]

Simulating diffused reflection - in physics terms. A surface with lots of bump will blur the reflection - in physics terms.

Wikipedia: http://en.wikipedia.org/wiki/Diffuse_reflection

But in 3D back in the old days that was to heavy to render (and too much bump setups) - so they made reflection blurring. And a lot of other ways to do it. (specular + gloss settings) In lightwave you can only use these value's 4% - 8% - 16% - 32% etc otherwise you get noise. (I need to check if its in kray also)

Hope this helps...

[Janusz Biela]

The specular system I use only on plants (leafs) because is quite crazy idea to add there reflection...the amount of ray tracing calculation is huge. Specular has recurse zero so must be faster but this different is no so much big in Kray.
Kray is modern render engine so using blur instead specular is very recommended especially when this simulation is physical!
Personally I use only reflection blur

[Fabian-Eshloraque]

Hey Janusz,

How do you solve the translucency of the leaves? Been working on it... without many success.

Grtz,

Fabian