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egidoro

strange black

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Hi,
with VW 2017, in a small bathroom, I used two mirrors that form a 90 ° corner.
In the rendering, a strange black portion appears.
How can I fix this?
Thank you.

Cattura.JPG

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If this is a section viewport on a sheet layer, check that in the advanced properties section of the OIP that "Cast Shadows of Objects removed by section" is checked. That may work. Also check that you have a RW background assigned to the viewport.

 

Also check in your render settings that you have more than 1 bounce and that max reflections is set to more than 1. 3 or more tends to be fine.

 

That's all I can think of for now!

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Thanks Markdd,
I've tried everything you said, but the result has not changed.
However, this only happens in the viewport section and not with renderwork cameras.
This is very strange...

Cattura 1.JPG

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What is there to reflect in that mirror? Or is the mirror facing the empty area designated by the section cut?

If you change your renderworks background for the render style being used on the section viewport, does it still show black or does it appear differently?

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1 hour ago, JimW said:

What is there to reflect in that mirror? Or is the mirror facing the empty area designated by the section cut?

There are three mirrors on three orthogonal walls.
Each mirror reflects another mirror that is in front of him.

 

1 hour ago, JimW said:

If you change your renderworks background for the render style being used on the section viewport, does it still show black or does it appear differently?

Yes, if I change my renderworks background for the render style being used on the section viewport, does it still show black.

Edited by egidoro

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You could try to increase reflection depth (bounces) in your Render Style.

By default it is 3. Maybe that is too low.

 

Beside that, what already was said.

To be able to see Reflections, there has to be something that can be seen in Reflection.

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You are right. In the 3d model there are 2 parallel mirrors, so I had increase reflection depth up to 24, like the number of bounces between the mirrors.

Thanks to all.

Cattura.JPG

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1 hour ago, Markvl said:

What kind of project is this for if I may ask?

Thank you very much...
It is the half bathroom of a house under construction in italy.
If you like it, I can show other rooms in rendering.

Edited by egidoro

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3 minutes ago, egidoro said:

If you like it, I can show other rooms in rendering.

 

A no brainer :)

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I also like that very unique style.

 

The only thing that irritates me a bit is the C4D Physical Sky,

or better the missing ground plane to horizon, in the kitchen scene.

And maybe I would like the walls and ceilings in the Apartment scenes

less gray, or better have more modulation in Global Illumination so that

they "look" more white.

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12 hours ago, zoomer said:

The only thing that irritates me a bit is the C4D Physical Sky,

or better the missing ground plane to horizon, in the kitchen scene.

Zoomer, you're right. This is very bad.
I'll fix it soon.

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@zoomer Hi, newbie here - I'm having this problem too. I'm using custom renderworks settings to render many mirrors and glass panels, with the glass panels surrounded by mirrored walls (I tried to upload an image but it failed) this means lots of reflections-of-reflections-of-reflections.... but, so far I always get a black section at the back where a reflection in a mirror would be. I have changed the custom renderworks options, trying increasing 'Max reflections' more and more up to 30, and also indirect lighting options.... is there something I'm missing? I can't figure out how to get these last reflections to show!

 

Thanks!

'

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Normally a Renderer has 2 Settings,

the max. Number of Reflections AND the max. Number of transparency Rays.

(a Glass Pane as a Volume would need 2 Rays, 1x front + 1x back side)

I don't know C4D's default number or what VW has set internally.

elsewhere you can set an exit color for transparency (or refraction) Rays once

exceeded, typically black.

 

Could it be that your camera looks through many, many Glass panes ?

 

30 max. Reflexions is already a lot.

(I mostly decrease to 2 Reflections to save some render time and you hardly

notice more than a secondary reflection in most scenes (beside your special case))

But as Reflections aren't that intense for non-metals, the intensity for secondary

Reflections decreases fast, so the end result after exceeding the max. Reflections

should not be Black, but at least a material color, transparency or primary reflection.

 

If you can exclude that there is any black Background or black Object that could be

seen by a Reflection, it may be worth to try to deactivate your Glass's Refraction

(Usually IOR about 1.52) by setting the IOR (Index of Refraction) to 1.00

to see if that changes anything.

You can hardly notice Refraction of thin Glass Panes opposed to thick curved

transparent Geometries.

You could try to play with an absorption color and distance in transparency settings

to keep the darker Pane Edges.

And it is also worth to try to deactivate or test such absorption settings because

these could also lead to an unwanted darkening.

 

I wouldn't swear that the Black may not be any kind of Software Bug though 😉 

 

 

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And what was the solution ?

 

If I remember correctly you had another thread where you had linked a preview,

or was it someone else (?)

Edited by zoomer

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@zoomer I honestly am not sure as I changed a few of the settings at once; I decreased the max no. of reflections to around 24, and re-did all the custom settings to the same again to re-set it ... so maybe it was a glitch? I don't think I know enough about it to have worked it out, but as long as it works that's good for me!!

 

I have posted another thread trying to achieve a HDRI reflection in some of these panes too, perhaps you saw it there.

 

So much to get your head around when new to this software! This is a preview of what Im trying to do - have adjusted lighting etc since this last render thought!

Picture1.png

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@zoomer Actually, I wondered if there was also a way to make the reflections-of-reflections (etc etc), get darker as they move further down the 'mirror tunnel'. Much like you would see when looking into an actual mirror tunnel.... The reflections look great but there is no sense of depth - that you'd get from having a  darker wall behind the actual panel - so wondered if I could cheat this in the reflections?... I've attached pictures from the fast render to show what the glass looks like with dark behind, and then how it looks rendering now...

 

Thanks!

Picture2.png

Picture3.png

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All Materials Reflect with a Fresnel Curve.

That means that Reflection starts with a certain value when you look perpendicular to

a Face and goes up to 100% until you look parallel to the Face.

Glass starts with a very low value, like all dielectrics, just about 5 %.

 

5% is not much and will easily dominated by the rest of 95% coming from Transparency

that shows what is behind the Glass.

(But 5% can be much if look outside of your Window at dark night from your lit room)

 

The Fresnel look from angle dependency is what make a rendered Glass look and feel

like a real Glass.

 

If you take a VW Glass Material, there is no real Fresnel Curve Reflection Shader but the

usual "Glass" Shader in Reflection Channel does fake it in a linear fashion.

It has 2 colors. By default Black (= 0%) when looking perpendicular and White (=100%)

when looking along the Glass.

White is correct, but Black should be a 95% gray tone to allow the 5% Reflection at

perpendicular angle.

So to fake stronger Reflections, you could play with the Black value and change to maybe

a 80% gray value to get stronger initial Reflection without loosing the high Reflectiveness

when looking a long the Glass.

 

Beside that, the problem with Reflections is always that they need an suitable environment

around them to be able to be seen. The more contrasts and noise around, the better visible.

Maybe adding a few bright Spot Lights for some Highlights and a bit of dark (slim) furniture

could help to pronounce your Reflections.

(While large contrasts tend to flatten the depth impression of an Image)

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