OTOY Forums

Miko3D: What are the chances of you writing an explanation for what each of the nodes is doing in your shader. Or writing a version of it which maximises the new, non-metalic Octane exporter. I'm happy I can get the spec and roughness to be ok, but I have no idea what this F0 doohicky is for

Hey Guys,

I have added the Shader for Blender in the main thread,

same workflow as in standalone,just reload the textures in the green Texture nodes and click render.

Again, if anyone is having issues setting it up with their 3D package, just drop me a pm.

Thx,

Mikel.

Thanks! This is awesome. Can´t wait to try it out!

gordonrobb wrote:Miko3D: What are the chances of you writing an explanation for what each of the nodes is doing in your shader. Or writing a version of it which maximises the new, non-metalic Octane exporter. I'm happy I can get the spec and roughness to be ok, but I have no idea what this F0 doohicky is for

Hey Gordon.as the shader is trying to mimic the basics of a Disney PBR and not just a texture match , there are a few nodes under the hood that you dont need to worry about ,they hack some functionality like retroreflection,desaturation at gracing angles for metals,closer match to a PBR microfacet model,etc.... one of my main complains of octane shader model is that it comes always way too reflective while using the glossy material,IMHO a good shader should be pretty much diffuse when cranking way up the roughness... this is not the case so I have added it in the shader.

the F0 reflection is a very important value,in PBR the reflection is always measured at F0 or facing angles(shading normals parallels to camera)in Octane and most of the other Offline renders the specular or reflection is the raw value before being affected by the Fresnel(or IOR in Octane),The problem is people thinks (with good reason) that as its called "specular" it just needs to be plugged to the "specular" slot and happy days,but this is far from true...dont forget the IOR is going to kick and for most dielectric materials you wont almost have any reflection in the material.



But We can build a spec/glossy material, at least a basic one, unfortunately im way too busy ,and dont forget V3 is coming tomorrow! so it could be nice to see how we can improve and make a proper PBR OpenSL matrial without any hacks

Now that the V3 alpha is coming out tomorrow, how soon do you think official Octane preset could be added to the Quixel suite?

The Blender shader works great! Very clever setup. Thank you Miko3D! Example image, just plugged in the texture maps and did not change any settings. As can be seen wood and metal can be mixed with good results on the same UV map thanks to the metalness node.
How do i upload this to live DB from Blender so others can use it?

This is the blender shader tree that Miko3D did. Very easy to set up,

miko3d wrote:

gordonrobb wrote:Miko3D: What are the chances of you writing an explanation for what each of the nodes is doing in your shader. Or writing a version of it which maximises the new, non-metalic Octane exporter. I'm happy I can get the spec and roughness to be ok, but I have no idea what this F0 doohicky is for

Hey Gordon.as the shader is trying to mimic the basics of a Disney PBR and not just a texture match , there are a few nodes under the hood that you dont need to worry about ,they hack some functionality like retroreflection,desaturation at gracing angles for metals,closer match to a PBR microfacet model,etc.... one of my main complains of octane shader model is that it comes always way too reflective while using the glossy material,IMHO a good shader should be pretty much diffuse when cranking way up the roughness... this is not the case so I have added it in the shader.

the F0 reflection is a very important value,in PBR the reflection is always measured at F0 or facing angles(shading normals parallels to camera)in Octane and most of the other Offline renders the specular or reflection is the raw value before being affected by the Fresnel(or IOR in Octane),The problem is people thinks (with good reason) that as its called "specular" it just needs to be plugged to the "specular" slot and happy days,but this is far from true...dont forget the IOR is going to kick and for most dielectric materials you wont almost have any reflection in the material.



But We can build a spec/glossy material, at least a basic one, unfortunately im way too busy ,and dont forget V3 is coming tomorrow! so it could be nice to see how we can improve and make a proper PBR OpenSL matrial without any hacks

Thanks for the explanation. I'll read it a few times to see if I understand it . The issue is with your material, it's using the gradient node to remap the texure (gamma curve I guess). and the lw plugin does not seem to do it the same. I look forward to see what V3 brings.

miko3d wrote: one of my main complains of octane shader model is that it comes always way too reflective while using the glossy material,IMHO a good shader should be pretty much diffuse when cranking way up the roughness... this is not the case so I have added it in the shader.

Hmm, When I look at a glossy material in the Lightwave plugin, with a roughness of 100% (1 in standalone) it is more or less diffuse.

miko3d wrote: the F0 reflection is a very important value,in PBR the reflection is always measured at F0 or facing angles(shading normals parallels to camera)in Octane and most of the other Offline renders the specular or reflection is the raw value before being affected by the Fresnel(or IOR in Octane),The problem is people thinks (with good reason) that as its called "specular" it just needs to be plugged to the "specular" slot and happy days,but this is far from true...dont forget the IOR is going to kick and for most dielectric materials you wont almost have any reflection in the material.

I normally just have the IOR set to 1 and it invariably looks quite good. However, I have thought thought you could have a metal and non-metal glossy material node. Set the IOR's to different values for each, and mix them based on a high contrast version of the specular texture. I've had good success with that.

So regarding this F0. Is there a way to adjust the specular texture, to compensate for the fact that the IOR will mess it up? My brain wont tell me what needs to be a adjusted with it And is this done in your shader? Perhaps I can pick it a part to understand what I'd need to do. [/quote]

miko3d wrote: But We can build a spec/glossy material, at least a basic one, unfortunately im way too busy ,and dont forget V3 is coming tomorrow! so it could be nice to see how we can improve and make a proper PBR OpenSL matrial without any hacks

I have a basic one, but it doesn't use IOR, does not differentiate between metalic and non-metalic surfaces (although it can with the method I described) and does not take this F0 into consideration. Would love to pick your brain when you get your feet cleared a little. Perhaps in the Quixel hangout?

gordonrobb wrote:
The issue is with your material, it's using the gradient node to remap the texure (gamma curve I guess). and the lw plugin does not seem to do it the same.

yes, unfortunately each plugin is importing ORBX in its own way...very annoying however we can have a look to this if you want,

gordonrobb wrote:
Hmm, When I look at a glossy material in the Lightwave plugin, with a roughness of 100% (1 in standalone) it is more or less diffuse.

well,till you compare to a diffuse material,give a quick test on a red colored rounded object,set a standard dielectric IOR of 1.53 (4%reflective) and crack the roughness to 1,and spec to 1.

gordonrobb wrote:
I normally just have the IOR set to 1 and it invariably looks quite good. However, I have thought thought you could have a metal and non-metal glossy material node. Set the IOR's to different values for each, and mix them based on a high contrast version of the specular texture. I've had good success with that.

Setting up IOR to 1 will not make use of the fresnel in the shader,this is only realistic if you are planning to redo the fresnel using a fallof node,otherwise your reflections will be constant along the curvature of the objects, and even metals dont behave like that,dielectrics need to have a strong Fresnel effect.

gordonrobb wrote: So regarding this F0. Is there a way to adjust the specular texture, to compensate for the fact that the IOR will mess it up?

yes,for a glossy/spec you may have already tried this,out of my head:
1- IOR to 1 (like you are doing)to replace IOR with a custom fresnel
2-Custom fresnel:create a falloff,plug it to a mix "amount" node and connect to the first texture input of the mix node the Spec material from Quixel,leave the second input a white color.Plug the mix result to the Specular slot of the glossy material.Play with the skew factor of the falloff node or formore control plug in between a gradient to remap the falloff.
3- connect the inverted glossy texture form the Suite to the remap ramp node from my shader,(the one with lots of steps) and plug it to the roughness
4-plug the albedo to diffuse.
5-plug normal/bump
This should give you a basic material you may be happy with.