need help with Cinema4D fresnel

[N.G.]

How do I mix the materials through a Fresnel map?

[zeitmeister]

The C4D fresnel shader isn't supported.
Perhaps you can search this forum about fresnel; there is an effect with ISL you can use.

[wlf_alex]

Who can show an example of how to use this effect in 4D?

[Mor4us]

Code: Select all

def eval(vec3 pos) vec3 :
lerp(
vec3(0, 0, 0),
vec3(1.0, 1.0, 1.0),
maxCosTheta()
                   )

filled in an ISL Shader should do the trick
the both vec3() are the fresnel colors as rgb (1.0=255)
you can now blend your ISL Shader via "ISL Blend Shader" with the desired map or shader of your choice

best regards

[wlf_alex]

Many thanks, Mor4us! This topic really has been confirmed and you will do it again. It's really simple But now another question. Is it possible to just mix the textures?

regards..

[N.G.]

How to fix error?

[N.G.]

why so difficult?

[galinette]

Hi NG,

I think minCosTheta and maxCosTheta cannot be used in a blend shader for physical reasons (it's then easy to break energy conservation). Also, you are using a color shader (returning a RGB vec3) in a blend shader slot (which must return a single number). Both are triggering errors.

So you should not use a blend material for this. Just use a diffuse or phong material, and use the shader in the diffuse channel.
For red/blue just use:

Code: Select all

def eval(vec3 pos) vec3 :
lerp(
vec3(1.0, 0, 0),
vec3(0, 0, 1.0),
maxCosTheta() )

Also, you could use minCosTheta instead of maxCosTheta, the effect will be slightly different.

I personally use 1.0 - pow(1.0 - (2.0/(1.0/maxCosTheta() + 1.0/minCosTheta())), 5.0) as the lerp function

Etienne

[N.G.]

Hi NG,

I think minCosTheta and maxCosTheta cannot be used in a blend shader for physical reasons (it's then easy to break energy conservation). Also, you are using a color shader (returning a RGB vec3) in a blend shader slot (which must return a single number). Both are triggering errors.

So you should not use a blend material for this. Just use a diffuse or phong material, and use the shader in the diffuse channel.
For red/blue just use:

Code: Select all

def eval(vec3 pos) vec3 :
lerp(
vec3(1.0, 0, 0),
vec3(0, 0, 1.0),
maxCosTheta() )

Also, you could use minCosTheta instead of maxCosTheta, the effect will be slightly different.

I personally use 1.0 - pow(1.0 - (2.0/(1.0/maxCosTheta() + 1.0/minCosTheta())), 5.0) as the lerp function

Etienne

how can I mix the two textures then? I'm confused.

[N.G.]

remains impossible to blend the two textures through Fresnel falloff, or error, or the effect is not the same.

[Zom-B]

remains impossible to blend the two textures through Fresnel falloff, or error, or the effect is not the same.

exactly!

[N.G.]

me sad.

[OnoSendai]

It's possible, just requires some ISL.

[N.G.]

It's possible, just requires some ISL.

Can you give an example? very need

[wlf_alex]

It's possible, just requires some ISL.

Can you give an example? very need

+10
pls-pls-pls !!!