Architectural Glass - shopfront reflections

[dcauldwell_cg]

Latest project - a small coffee shop. It is really a study in the use of architectural glass. I set up a billboard opposite the model, with a photo of the streetscene, which provides the reflections. Getting the internal lighting levels right was tricky. I didn't use the linked glass material as I find it keeps coming out too 'muddy' so I just used the vray clear glass which provides better clarity. (door to shop still to be installed!)

[dalomar_cg]

Re: Architectural Glass - shopfront reflections

Personally, I've found that the standard settings for glass doesn't really work as well as I'd like for Architectural Glass. For me the reflections are too faint at angles that are close to straight on (like your render there) and for glancing angles the reflections are too strong and block out whats happening behind the glass.

My solution...If you open up the fresnel map in the reflections you'll notice two colors, probably black and white. Those are the minimum and maximum reflection values respectively. So I bump up the black a bit to about 50-60 and kick the white down to about 210-220. Try that out and see if you like those results a little better.

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Thanks for the comments Damien.

I actually thought that the refelections were about right, but you've now got me intrigued, so I will enbark on a series of tests with different glass settings, and compare them with a photograph of the actual scene.
I thought that the amount of reflection was governed by:-
a) the brightness of the scene being reflected (in this case it isn't illuminated by the sun - just global illumination)
b) the brightness of the scene behind the glass (i.e. if the lights in the shop were all off, and thus it was dark in the shop, then the reflections in the glass would be greater.
In the above posting I increased the lighting levels in the shop so that the inside became more prominent - just what you would do with lighting in a shop!

I will post the results of my tests soon.

Regards
David

[nomeradona_cg]

Re: Architectural Glass - shopfront reflections

i am stuggling too with architectural glass using vray. i have read the manual and many of this things here. my problem really is making the light going through the glass. i dont still have the full control on this.

another thing i found out, it seems that when you tick overide sun parameter's, vray will remember this setting. Then if you adjust the sun location, vray sun will not be will not be updated based on the new location. can you please look at this.

[dalomar_cg]

Re: Architectural Glass - shopfront reflections

@ David

You are correct with all of your observations. The amount of reflection will change depending on how much light is coming from each side. You also have the challenge of balancing the reflections from the outside with looking in and seeing the actual subject matter of the render. I just wanted to point out that there's abit more control over those different aspect of the glass material than most would think. Test it for yourself and see what works for you.

@ Nomeradona

If you want the shadows to come through the glass then check Affect Shadows in the Refraction layer. That will basically fake the caustics and allow the shadows to be seen through the glass. If that doesn't work then get back to me b/c there's another work around for things. I also check affect alpha as this is useful for archviz renders. As far as the sun, Joe knows and is working on ironing that one out.

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Damien

thanks for the comments. I've tried some comparative tests with different glass settings (I put the settings on the shopfront fascia in the renders)

First I have deleted the 'refration layer' as it wasn't helping.

Then I tried using different luminence levels of white in the 'fresnel color' 240, and 120 and could see only very slight difference (120 seems to allow a minute amount of extra light through)





Then, keeping the 'fresnel color' at 240, I changed the 'refract colour' luminence levels to 60, 120, and 180
and the intensity of the reflections increases with each setting







and for comparison, here is a shot of the real shopfront. As you can see the actual reflections look like a 240,180, but as you say Damien, if I used this setting I wouldn't see what was going on in the shop!

So, for presentation purposes, I think the 240-60 is the one to use. It gives a hint of reflection without drowning out the view through the window. At least I now know which setting to adjust to get the effect.

[dalomar_cg]

Re: Architectural Glass - shopfront reflections

Great tests. You can definitely see a difference between the 240,60 and the first render. If the Refraction Layer is not doing anything for your material, then its probably because the geometry that your applying it to is not a solid, but a single surface. Proper refraction needs an entrance surface and an exit surface, without those, the it doesn't act correctly. Use the Push/Pull tool to extrude those faces to make a solid.

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Thanks Damien.

Just to finish this off, and as some people are having trouble getting the sunlight in, here is the a view of the same model (same settings) from the inside. (It's all a bit crude at the moment - still work in progress). The glass here is 240-80 glass. (I can see me ordering glass like this, i.e. 240-80, from my local glazier!!)

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

This is the penultimate (!) internal view.
I'm just getting my head around glossiness etc, so I've tweaked some of the textures and added a little gloss and roughness to the floor.

Any comments on how I can improve very welcome.

[Ilay7k]

Re: Architectural Glass - shopfront reflections

Hello David!
Can you upload results(vismats)of your tests?
Thanks a'lot
Ilay.

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Ilay,

Which 'vismats' are you referring to? Do you mean the glass material?

David

[Ilay7k]

Re: Architectural Glass - shopfront reflections

Yes, i try to make it(in accord with your test). may be i loose something :'(...

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Ilay,

If you want the vismat then e-mail me your address I am happy to send you the glass.
(I can't upload it to this site.)

David

[Ilay7k]

Re: Architectural Glass - shopfront reflections

David i send e-mail address to "your messages".

Ilay

[dcauldwell_cg]

Re: Architectural Glass - shopfront reflections

Ilay

I've put the 'architectural glass' vismat in the downloads section. Hope you find that it works ok for you.
(I've just work out how to post)

David