new visible Environment node -> wish

[v-cube]

Hello,

since my old post is buried in the now probably abandoned development release thread, I dare to repost it again since the issue is still valid for octane 3.0 and IMHO very important.

viewtopic.php?f=33&t=54110




I think it would be the best idea in regards to predictability to have 4 separate user controllable map slots each with their own multiplier, which only affect their specific purpose:

1. Environment for lightning . This would be used for distributing the light and in case no additional maps are used in the other slots act as a source for these undefined slots.

2. Environment for reflections. This would affect the reflections for specular and glossy materials. It would not contribute to any direct or diffuse light distribution.

3. Environment for refractions. This would affect the refractions for specular materials. It would not contribute to any direct or diffuse light distribution. This is not so important IMHO and could eventually be locked to the reflection slot, however in some cases it can be also be desirable to have control here, so if it is not to much work, I would also implement it.

4. Environment for backplate/background. This environment would be very important for post production, since here we would be able to control the border region of elements like trees against their background, this would enable us to adjust the background in a way it would fit against a custom background used in post production , e.g. a picture taken on site for photomontage.

I am aware that this might confuse an average octane user so you can maybe implement it in a way that you first have to click the option "use multiple environments (advanced)" before these slots become visible...

best regards

Andreas Walther

hi Andreas,

The visible environment is used when a ray immediately hits the environment or hits the environment on path termination. For reflections and refractions we use the normal environment. For diffuse materials or rough materials, the situation is a bit more complex. When we hit one of those materials, we calculate direct light and trace a reflection ray, this direct light calculation uses the normal environment and the reflected ray uses the visible environment (if the reflected ray goes into the environment) hence the effect of both environments.

The idea is that you can use the visible environment to "hack" what is visible directly or for "clear" reflections/refractions of the background in materials (i.e. in a mirror or glass). We could tweak it for example that the visible environment is only seen when the ray directly hits the environment or used only for glossy/specular materials with low roughness. But we need to have a clear picture of what exactly is needed then.

cheers,
Thomas

[calus]

Right Andreas, you perfectly described the ideal implementation.

[Draydin_r]

I would Third this if possible. It certainly would make building out large environmental scenes much easier!

[funk]

+1

Modo (my host application) already works this way in it's own renderer. Many commercial sIBL packs will usually come with 3 textures: background, lighting and reflection/refraction (used for both)

[DinoMuhic]

+1

[pegot]

+1

[stratified]

Hi Andreas,

Thanks for the feedback. I've created a ticket in our tracker so that it doesn't get lost. We will revise this later. Probably not in this 3.0 release.

cheers,
Thomas

[stratified]

We are currently revisiting this but we want to figure out how exactly this feature is going to be used (not how it should be implemented). Is there a particular workflow you are using here or is this in conjunction with some other tool? Maybe some links to video tutorials where this technique is used?

If we can, we would like to avoid having 4 different environments and keep our original 2 environments. The key question is when to use which environment.

The visible environment would be used if:

• The camera ray directly hits the environment. In this case the visible environment would act as a backplate. (backplate case).
• For reflections and refractions on polished (low roughness) specular and glossy materials (reflection/refraction case). These are reflections/refractions that are clearly visible.

The normal environment would be used if:

• There is no visible environment available.
• Reflections involving diffuse materials or rough specular / glossy materials (normal case). In this case the reflections from the environment will be very blurred.
• On path termination after multiple bounces (path termination case).

Here are pictures for the different cases that can be encountered during rendering.

backplate_case.png

polished_material_case.png

normal_material.png

path_termination_case.png

There are still some open questions here:

• Should we use the visible environment in the reflection/refraction case only on the first bounce or for all bounces?
• In which environment should we end up after path termination?

Thanks,
Thomas

[Draydin_r]

Honestly, if Visible Background had the option to have/not have reflections/lighting operational that would work wonders.

However, I think the problem that some people are looking at is the older workflow of having an environment map and a reflection map to work with. This would allow to light with one map but have whatever enviroment reflections you want in the scene based on what map you use. Or you could have none of the reflections. Eitherway this gives an enormous amount of flex to work with in some scenes.

The Ideal in my mind if would function like this:

If I need to have my lighting and reflections separate or have them removed all together for a backplate
Visible Background:
Reflections Btn: on/off
Separate Reflection Map Field/btn: Link to file
Lighting Btn: on/off

For everything else:
Normal Environment:
As is

The only thing more awesome is if we could even exclude objects and lights from the reflection calculation or even control what reflections see what objects. Somewhat like an exclusion list.

A good example would be to have a mirror, light and a metal sphere. In this case the metal sphere can see the light and the mirror but the mirror can't see the metal sphere and the metal sphere doesn't reflect it's own reflection in the mirror but does receive a reflection of the mirror and of the reflection of the light in the mirror. It should also allow lights to not be reflected. That said I understand this is an extremely complex feature request, it just would save so much photoshop time if it could be done.

Also on an unrelated topic, is it possible to assign an alpha channel value to an object? Right now it can be problematic to have the anything behind glass that has an affect alpha applied or to have something you you want to remove from the scene without removing anything else or have to deal with a pile of layers. Would it be possible to have something like lightwave's ability to assign an alpha channel override to a material or an object? Hell, taken one step further it would awesome to be able to apply an alpha channel texture to a material and have it register in render with out affecting the scene like opacity changes would!

But that's my two cents, what are everyone else's thoughts?

Draydin_r

[HHbomb]

A per material option could be great !!!!