No light coming through windows - help please

[redi]

Hi all

We are busy with an interior scene and we are having a problem with the lighting - the windows do not let any light through. Even if we crank the light multipliers all the way up to 30, nothing changes. We have tried changing materials and rebuiling the model (the windows). We have turned off generate GI on all the glass. We are using Vray plane lights outside the windows, with HDRI in used for the environment and a Vray dome light on the interior. Anybody have any ideas as to what could be wrong? Anybody want to download the scene to have a look?http://imagine-group.com/jurg/scene.zip

[nvanherpt]

if you are using vray glass, ensure "Affect Shadows" is ticked in the Refraction area of the material in the Material Editor.

[ene.xis]

Re: No light coming through windows - help please

We are using Vray plane lights outside the windows

this vray light will block light coming from the outside...if u want to keep this light source u have to add another vray light in front of this set to skylight portal!

[ene.xis]

u got light

check ur glass:
turn on affect shadows!
remove that darn plane! and check LWF threads

quick and dirty test....

[Clifton Santiago]

Yes, Vray planar lights outside window, even if invisible, will block other Vray lights from entering interior. However a standard max light will penetrate vray planar lights...

[Frances]

u got light

check ur glass:
turn on affect shadows!
remove that darn plane! and check LWF threads
....

This LWF thing is getting out of hand if you're going to be rude to people just because they are beginners and don't know about advanced techniques. If LWF is soooooo important, the default settings for VRay should be geared specifically for LWF.

Meanwhile, people who are new to Vray should not be expected to search for LWF. If this forum is going to be a place where people are only willing to help those using their flavor of LWF, then that's a sad thing.

[plastic_]

well the LWF _is_ amazing.
i also ignored it for a long time, because i thought all this talk about gamma, ICC profiles, floating point colors, was a bit annoying.
but after giving it a try it really turns out to be a massive improvement.
everything seems to be much easier now, the light behaves more like i'm used to with photography.
i always used the shadow/highlight adjustment tool in photoshop, to brighten up the shadows, not knowing that shifting the levels curve was actually nessecary, to get correct results with the wrong gamma workflow.

[ene.xis]

frances:
i m not gonna help anybody based on wether he/she uses LWF or any thing else...
i m on tight deadline...full of work i took a look at the scene posted here, and i think he can get away much better without those light panels on windows, wich would became hell to work with considering th scene, and i assume that whit lwf he can get away much smoother and yet improve his workflow....
sorry...

[studioDIM]

If LWF is soooooo important, the default settings for VRay should be geared specifically for LWF.

Please don't!
I work entirely linearly, i'd be fairly disappointed if this happened

Lele

[Frances]

frances:
i m not gonna help anybody based on wether he/she uses LWF or any thing else...
i m on tight deadline...full of work i took a look at the scene posted here, and i think he can get away much better without those light panels on windows, wich would became hell to work with considering th scene, and i assume that whit lwf he can get away much smoother and yet improve his workflow....

Then why didn't you say so in the first place? Even if you really don't have time to help people, they don't have to know it.

I'm well aware of the benefits of LWF and am in the process of incorporating it into my own work. But just because we know about it, doesn't mean everyone does.

[ene.xis]

that s the reason why i mentioned it frances...
i don t think i mentioned has something obvious or that he should have that knowledge....

[Morbid Angel]

ene has got it correct. However I would like to explain why such thing is happening;
Affect shadows is a "fake" to allow fast renderings of light passed through glass. However its physicly incorrect. The reason for this is, every light energy that has passed through glass has become a caustic energy. Therefore you need caustics. In his example scene, the refractive caustics are turned on, however because of biased method - irmap, caustics will never show, thus the illumination from passed light through glass will not appear, producing such result as we see at the default render of this example scene.
So, to see the light passed we eather turn on affect shadows, which is imo a good cheat for a fast and effective rendering time, or we turn off affect shadows, turn on refractive caustics and set illumination method to qmc/lc or lc/lc in ppt and wait for many hours for the light to show.
Here are some research tests I've done for maxwell forum, but they also apply to this:
Image 1, shows maxwell caustics illumination through glass



Image 2 shows vray glass with affect shadows



image 3 shows when affect shadows is turned off, exactly the same as what redi has



And image 4 shows physical caustics in vray with affect shadows off, and refractive caustics on

[redi]

Wow - thanks everybody for your responses - I really appreciate it! Will definately check out this LWF stuff too!

[ene.xis]

[redi]

Thank you Morbid Angel for that cool explanation!