Yafray area lights (problem)

[Curvespace]

Hi all,

First post, so go easy on me ;)

I'm rendering inside a closed room with two windows. For the windows I am using rectangular area lamps. The problem I'm having is that the room is rendering (with Yafray) completely pitch black. I have copied the render and lamp settings wholesale from this (http://www.katorlegaz.com/index.php?a=thumbs&c=Blender_3D_Model_Repository&p=yafray) example (exp_test2.zip (http://www.katorlegaz.com/downloads/Blender_3D_Model_Repository/yafray/exp_test2.zip)), which incidently renders just fine. I've tried kicking up the lamp energy and various gamma settings, but to no avail. I'm using 'FullGI settings.

The area lamps are just inside the the face of the windows (which are out of shot). My only solution so far has been to get rid of the vertices of the windows and put normal/sun lamps outside them, but it's not the effect I want.

I've looked around for ages on various forums, but most issues people are having with Yafray and darkness seem to be more related to reinstalling Yafray.

Any help would be much appreciated :)

[JDA]

Ok, did you check the normals?
Are they all pointing in the right direction?


http://download.blender.org/documentation/bc2004/Alejandro_Conty/

[Curvespace]

I'm pretty sure the normals are all ok (by that I assume you mean the face normals - ctrl N and all that?). The scene looks fine if I render using normal lamps, so I'm guessing it's not that.

I've had a read through that Yafray PDF and have followed the advice there for setting up arealights and emmiters in an interior room. I've achieved some amount of light by placing an emmiter material behind the arealight (which I wasn't doing before), but it's only a minimal amount of light and no matter how much energy I give the arealights it doesn't make any difference.

I can't seem to achieve anything like the results in the simple examples in the link you gave me, but I'm sure all my settings are the same :(

I hope I'm making some sense here. Thanks for your help :)

[JDA]

You can send me the .blend if you want
and I'll take a look.
Just PM me for e-mail address.
Or post a link to the .blend.

[Curvespace]

Thanks for the offer, it's much appreciated. Here is the link:

http://ruder.co.uk/ftp/misc/bottle_0.273.blend

What is the 'beam' of arealights (not sure if that is the right word). Do they emmit light simply in a block in the direction they are facing or do they spread light out at all angles in the direction they are facing?

Thanks again.

[JDA]

Well I looked at your file
and there are a bunch of normals
pointing in the wrong direction.

What I do is select the mesh and
turn off Double Sided.
It's the green button under the Center
Cursor button. With Draw Normals activated it helps me
better find where there are normals pointing
in the wrong direction.

I suggest you remodel the room
and leave the windows open for now.
Turn Gamma up to either 2.0 or 2.2.
Build your rooms like they are in the real world.
Also you can do a test by turning off the Cache button
and turning on the Tune Photons Button.

[Curvespace]

I checked the normals and couldn't find the offending ones that you speak of. If the problem were normals then wouldn't that still be the case when I turned the arealights to simple lamps? I'll have another look; being the noob here means I'm more than likely at fault. ;)

I agree with what you say about modelling the whole room. Originally this was just a render of the bottle and I added the corner of the room as an after-thought to make a more interesting render. This is my first non-tutorial attempt at doing anything with Blender (apart from the obligitoray shiny balls on tile floors type stuff).

Unfortunatly I've not got time to remodel the room on this project, as my friend needs it tonight for her Uni work, so I'll change the windows for open spaces and then work with lights outside. Hopefully I'll be able to get a workable result. I've got a whole bunch of texture questions up my sleeve but I'll save them for another day and another thread.

Thanks for your time, it's very much appreciated. It's great to see that Blender has a community that's as good as the software :)

[Myke]

I don't know if you still need help but I looked at the blend and so I thought, I could post something, too.

The lighting setup seems to be fine (it's very obvious that you made good use of the information available about Yafray...very often someone asks why the area light doesn't add light to the scene with Yafray instead of simply reading that pdf above...), the problem is, as mentioned before, that you modelled a closed room. If you remove the emitter planes and open the small window instead (that means, delete the face covering it) you will see that the scene looks very similar to the one with the emitter planes. The difference is that the light now has the color of the world BG.
I could not open the second one easily, so, as you said, a new model would help a lot. Open windows make it much easier to give it a natural look, at least in my opinion.

I'd also advice to look out for Alvaro's post about the usage of exposure and gamma correction...very helpful and definitely worth checking out, the little tips improved my current scene a lot.

[Curvespace]

Thanks for the advice. :)

I've already deleted the faces of the windows and that has made a difference. I've also played around with adding other windows to the room, but I'm still not really getting the results I was hoping for, though at least now I have things set-up correctly and it's simply a question of me 'getting it right'.

I'll now remove the emmiter planes like you suggest. Slowly, but surely this is starting to make more sense to me. Now I've just gotta fix the 'noise problem' ;)

[shr1k]

area lights in yafray must be square I didn't look at your blend so I don't know if yours are. but I have made the lights rectangular and had the problem you describe.
ok had a look and they were rectangle I made them square and it works you will need some adjustment the light at the intersection of wall mesh and light looks strange.

[Curvespace]

Really? That seems kinda odd. Will look into it. My rectangular ones seem to be working ok now though. Perhaps using multiple squarelamps to fill a rectangular window then?

[oldskoolPunk]

I have also noticed in Yafray that area lights, and point lights with a radius of more than 1, do not work with the photons button pressed and the quality set to none.

[t3d]

Iv'e found your problem ( but don't know if it's for some help now though ).
It was a little tiny thing - move the plane and lights and set the arealight to square. Better explaind with a couple of images:

From this: (the light is behind a face belonging to the room)

http://img354.imageshack.us/img354/4673/yafroom0011gn.jpg

To:
http://img72.imageshack.us/img72/1718/yafroom0023fc.jpg


Results in:
http://img72.imageshack.us/img72/4357/yafroomrender0py.jpg

Happy blendering!
/ t3d

[Myke]

Just out of curiousity but why do area lights need to be square? If I think about it, I have never used rectangular ones with Yafray, so, does anyone know what kind of difference they make?