OctaneRender™ Standalone 3.08 TEST 4

[roeland]

Shouldn't a "metallic material" with n = 1.5, k = 0, look the same as a glossy material with IOR = 1.5?
The metallic material is shinier. Is this a case of using the wrong fresnel formula again? You've done this in the past and had to switch to non polarised
EDIT: Setting n = 0, and specular = 0.04 (4% = IOR 1.5), is getting much closer to the glossy material (although fresnel is a bit different due to schlick's approximation). So something is wrong with your n/k formula

Yes we are using a simplified form for the Fresnel equations for complex IOR, which works best for metals but which is not accurate for the usual IORs for dielectric materials.

The Schlick approximation is only used on metallic materials when you set the IOR to 0, in that case the metallic color is assumed to be the reflectance at normal incidence.

-Roeland

[funk]

Yes we are using a simplified form for the Fresnel equations for complex IOR, which works best for metals but which is not accurate for the usual IORs for dielectric materials.

So we basically have a metallic node, with 2 fresnel approximations...

I'm kind of confused how we are meant to use the n/k values along with specular color?

eg If I was going to get n/k for gold, I would visit https://refractiveindex.info/, select gold, then get 3 sets of n/k values for R/G/B (approx wavelengths 0.65, 0.55, 0.45).

With the metallic node, there is no way to enter 3 sets of values. So how are we meant to know what values to enter into n/k and specular color?

I "could" create the specular color by getting the 0 degree reflectance values (shown later down the page), for R,G and B, but entering a value for n/k is still guesswork (how?) and would "scale" this color anyway (according to viewtopic.php?f=33&t=63219 )

[Draydin_r]

Hi Draydin,
do you mind to post a screenshot of your settings with preview of the image used in rotation?

The attachment 54DA5BB1-3E3A-4562-B023-41D7BD192C7C.jpeg is no longer available

ciao beppe

Ultra basic settings really, which was why I was perplexed. But now that it's been said that this is a problem they are working on thats good to know!

Draydin_r

[gardeler]

I'm doing a project where we are rendering lots of particles via alembic files in vray. I would like to test them in octane to compare, but I cant find a setting to override particle size? (like the hair thickness.) Did we use to have that at some point, or is it just something I made up in my mind? Is there a way to do an override?

(I have only tested in octane 3.07)

[abstrax]

I'm doing a project where we are rendering lots of particles via alembic files in vray. I would like to test them in octane to compare, but I cant find a setting to override particle size? (like the hair thickness.) Did we use to have that at some point, or is it just something I made up in my mind? Is there a way to do an override?

(I have only tested in octane 3.07)

I just checked it and Alembic allows the storage of particle sizes and Octane imports and exports these. If you use some other 3D application to export to Alembic you may have to set the export options accordingly, but I've got no clue how that can be done. Sorry.

[gardeler]

I'm doing a project where we are rendering lots of particles via alembic files in vray. I would like to test them in octane to compare, but I cant find a setting to override particle size? (like the hair thickness.) Did we use to have that at some point, or is it just something I made up in my mind? Is there a way to do an override?

(I have only tested in octane 3.07)

I just checked it and Alembic allows the storage of particle sizes and Octane imports and exports these. If you use some other 3D application to export to Alembic you may have to set the export options accordingly, but I've got no clue how that can be done. Sorry.

Thank you for your quick response! I can in deed set the size, but we use the option in vray to override that and set it when we render. It would require a complete re-simulation everytime you wanted to change them in a shot.

It would be amazing to have "attribute nodes" in stand alone, as in houdini, where you could override things like a new particle radius, camera settings and such, as I find my self often having to go back into the other app just to change a number on something. Maybe that is already possible with the script nodes?

[abstrax]

Thank you for your quick response! I can in deed set the size, but we use the option in vray to override that and set it when we render. It would require a complete re-simulation everytime you wanted to change them in a shot.

It would be amazing to have "attribute nodes" in stand alone, as in houdini, where you could override things like a new particle radius, camera settings and such, as I find my self often having to go back into the other app just to change a number on something. Maybe that is already possible with the script nodes?

I see. That's currently not possible. The only thing you can try is to not export any particle sizes at all in which case the default sphere radius will be used which is defined in the Alembic import preferences.

[gardeler]

Thank you for your quick response! I can in deed set the size, but we use the option in vray to override that and set it when we render. It would require a complete re-simulation everytime you wanted to change them in a shot.

It would be amazing to have "attribute nodes" in stand alone, as in houdini, where you could override things like a new particle radius, camera settings and such, as I find my self often having to go back into the other app just to change a number on something. Maybe that is already possible with the script nodes?

I see. That's currently not possible. The only thing you can try is to not export any particle sizes at all in which case the default sphere radius will be used which is defined in the Alembic import preferences.

Ok, hope that could change in the future. Thanks for helping out.

/Martin

[coilbook]

when will already add fake Godrays and Volumelights, wireframe shader?
3.08?

looking at octane 4 I guess never I guess they dont believe that nice volume lights can create cool render scenes. We only god flat fog in octane