How to make "glass" less reflective? (Renderworks)

[line-weight]

 

The image is an extract from a cutaway rendering. Kind of white card/balsa style.

 

It's modelling a glass-to-glass corner.

 

I don't want to see so much reflection there, in that corner. Partly the issue here, I think, is that these are triple glazed windows and they are modelled as such. So there are 3 layers of reflections going on. Of course I could replace with one solid piece of glass for the purposes of this rendering but would rather not if possible.

 

I thought I'd be able to dial the reflections right down ... but I can't seem to find the setting that lets me do this.

 

Here are the "reflectivity" settings for the material I'm using.

 

 

I thought I could just reduce "Reflection" to a very low percentage. But even setting it at 1 or zero seems to have little effect.

 

Where am I going wrong?

 

 

[Dave Donley]

For "architectural" glass and rendering people often set index of refraction to 1.0 even though this is not strictly accurate.  This might affect the reflections.  Also what about using glass reflection instead of plastic?

[zoomer]

You have a "glass" Roughness of 30%.

Is this intentionally ? (frosted glass ?)

 

Not only for glass, but all dielectric Materials (basically all my render materials), I prefer the "Glass" Reflection Shader.
As it allows to fake the Fresnel effect. If you look at a glass at normal angle it will only have about 5 % of reflexion, if you look at it at glazing angle it will be 100% reflexion. Glass Reflexion offers 2 color inputs for these (white for 100%, black for 0 %)

 

So for a realistic Glass, keep the white color but brighten up the default black to a VW 90% gray color => 10 % reflexion at normal angle. If only for that shot and still too much, because of the tripple glazing, you can set it back to 100% black and further tone the white input down.
 

AFAIK the plastic reflexion will use the same reflexion value - no matter at which angle ....

[line-weight]

13 hours ago, zoomer said:

You have a "glass" Roughness of 30%.

Is this intentionally ? (frosted glass ?)

 

Not only for glass, but all dielectric Materials (basically all my render materials), I prefer the "Glass" Reflection Shader.
As it allows to fake the Fresnel effect. If you look at a glass at normal angle it will only have about 5 % of reflexion, if you look at it at glazing angle it will be 100% reflexion. Glass Reflexion offers 2 color inputs for these (white for 100%, black for 0 %)

 

So for a realistic Glass, keep the white color but brighten up the default black to a VW 90% gray color => 10 % reflexion at normal angle. If only for that shot and still too much, because of the tripple glazing, you can set it back to 100% black and further tone the white input down.
 

AFAIK the plastic reflexion will use the same reflexion value - no matter at which angle ....

 

Thanks @zoomer

 

I've tried as you suggest with the glass shader, but making adjustments to those two grayscale inputs seems to have no effect on my render at all. I am going to have to do a bit of troubleshooting to see what's going on. Maybe it is something in my render settings.

[line-weight]

Here's a test file and a screenshot from it.

As far as I can see, adjusting those settings has no discernable effect on the reflections visible in the render.

 

glass test.vwx

[zoomer]

3 minutes ago, line-weight said:

but making adjustments to those two grayscale inputs seems to have no effect on my render at all.

 

Hmmh, I never checked that. Maybe it does not work ?
I just trusted the input. And as I only change "black" to 90% gray (as VW default color palette does not offer a 95%) which isn't much change from default that would be noticed. At least I never realized that I would not have no glass reflection at normal angle because it ignores my 90% input and uses black instead.

[VIRTUALENVIRONS]

Try adjusting your transparent settings as opposed to reflection.  Change glass to colour and try some renderings.

[zoomer]

3 hours ago, line-weight said:

Here's a test file and a screenshot from it.

Nice test.

 

I am not completely sure but I might see some subtle differences (?) between glass 1 and glass 2.

Or maybe it just doesn't work (?)

 

The problem here is that the angle we see the orange reflection I nearly about 45° to normal, for both glass panes. I think the glass reflection shader works linearly, not by a real fresnel curve. So what we see is about the mix of both, edge and center color settings. And the tested mix of gray tones difference may not be enough to distinguish (?)

 

Alternatively you could choose a pedestrian camera position more from the left, so you can see glass pane left nearly from glancing angle/edge color value and glass pane 2 more frontal/center color value. Maybe even making the glass opak and black (while keeping the scene still lit properly) as it is only about the reflection effect.

 

When I check reflection settings, I usually just set a sphere. And estimate the reflection amount of its environment.

I did that recently in Blender, when I got confused with results - as I had misinterpreted some inputs of the principled BSDF settings. In that case that black sphere test worked and illustrated well - once I got used to the Settings.

 

 

[line-weight]

32 minutes ago, VIRTUALENVIRONS said:

Try adjusting your transparent settings as opposed to reflection.  Change glass to colour and try some renderings.

Changing the transparency or colour settings has the kinds of results I expect. It doesn't affect what's going on with the reflections though.

[line-weight]

Here's what happens, going back to the "plastic" shader.

 

There is some difference between reflectivity at 100% vs 0%.

 

But 0% certainly doesn't reduce the reflections to zero!

 

[line-weight]

7 minutes ago, zoomer said:

Alternatively you could choose a pedestrian camera position more from the left, so you can see glass pane left nearly from glancing angle/edge color value and glass pane 2 more frontal/center color value.

 

Here's what happens... if there is any difference between the renders it's very subtle.

 

[line-weight]

For completeness... here's what happens with the "mirror" shader

 

[line-weight]

Here's an updated version of the test file itself, if any wants to try and replicate.

 

glass test.vwx

 

I wonder if I should report this as a bug. I've tried it in VW2023 as well as VW2025, with the same results.

[zoomer]

Hmmh, indeed, glass reflection Fresnel-Fake-Effect is vääääääääry subtle ......

(that bit of shadow-like dark "cloud" in the dead center of the sphere)

 

It only does what I need - keeping reflection along normal low - but nothing more.

Indeed it looks terrible. And it does not translate color values correctly, looks more like only using values by 50%only, otherwise that dark center area should be totally black.

 

 

 

 

 

Untitled 1.vwx

Edited January 24 by zoomer

[zoomer]

1 hour ago, zoomer said:

And it does not translate color values correctly, looks more like only using values by 50%only, otherwise that dark center area should be totally black.

 

Sorry, it gets black - I had accidentally still 90% gray.

But it doesn't look much like a glass reflection though. Update :

 

[line-weight]

@zoomer I tried the "clear" texture that was in your file, in my original drawing, and at first I thought it was in some way better (from a reflections point of view). It's the one on the left below. But as soon as I changed the "transmission" value under transparency from 90% to 95% the undesired reflections re-appeared more strongly again (image on the right).

 

 

This doesn't feel right to me ... it doesn't feel like reflections should become more prominent as the material becomes more transparent.

[line-weight]

16 minutes ago, zoomer said:

 

Sorry, it gets black - I had accidentally still 90% gray.

But it doesn't look much like a glass reflection though. Update :

 

 

I realise things get more confusing because there is also a "fresnel" shader option under "color":

 

[line-weight]

20 hours ago, Dave Donley said:

For "architectural" glass and rendering people often set index of refraction to 1.0 even though this is not strictly accurate.  This might affect the reflections. 

I've just got around to trying this, and actually this does reduce the reflections quite a lot. Thanks. It doesn't really make sense but it works!

[zoomer]

 

Just now, line-weight said:

I realise things get more confusing because there is also a "fresnel" shader option under "color":

 

Haha, I tried that too. And hoped it would have some influence on the reflection too. But seems it is for Diffuse channel only.
I also tried a "deactivated" glass transparency - to be able to set an IOR, to maybe get a fresnel effect, but it is only for refraction.

 

Now I misused the Metallic Reflection.

Value black and 0% but activated clear coat reflection.
(which should use a standard dielectric's IOR of 1.5 or so - at least it looks a bit like)

 

 

 

So the most Fresnel impression for a dielectric material I could get in VW.

 

 

 

Untitled 2.vwx