Problems with Light levels..

[alfienoakes]

I am having some real problems with GI and general lighting levels.

 

I have set up a scene, and am just sorting out the lighting, before I add materials.

 

The attached scenes have GI skylight at 5, set to white, first bounce 1.5, second 1.

 

The direct light is a standard target direct, vrayshadows intensity set to 1.

 

The glass apertures, are a standard material, with opacity set at 7, with vraymap in reflections.

 

One of the images is only GI, but this looks way to weak for skylight.

 

As you can see, the light entering the room is just not powerful enough, yet if I turn any settings up to high, or add extra lights at the window, I get problems with the image over exposing, as is starting to happen on the work surface.

 

Any tips or clues would be great..

 

Vray free and Viz 2006 bay the way...

 

Andy

[Guest nazcaLine]

tthe main problem is the size of the window, i think. it's very small, and not enough light is allowed to get in, so as much as you increase the lights intensity, it'll be no difference. if you can't make the openings bigger by changing the design, then you may try an omni light inside as a fill light.

 

good luck.

[alfienoakes]

Cheers eduardo,

 

The thing is, this is my existing house, with an extension. The current set up is not disimilar to what is here, and it lets in allot more light then this.

 

Does Vray bounce light off of obbjects in the same way as radiosity? I only ask, as I have a house next door to me, and we must get quite allot of reflected light from them.

 

I will add a large dummy object, and see if it makes any difference.

 

Andy

[alfienoakes]

OK

 

Didn't add the dummy object, but did add some very basic colours, and 3 onmis next to each window.

 

They are inside the room, floating about midway up the windows..

 

Anyway, they seem to add a bit more light into the scene.. but I am now getting some strange results with materials.

 

The wall cupboards are the same materal as the floor cupboards, but have come out a completely different colour.

 

I have noticed this on a previous render that I have done.

 

Using Vray free and Viz 2006..??

 

Andy

[bdonay]

Try this link and download the Introduction to Interior Lighting pdf

http://cgarchitect.vismasters.com/catalog/viewproduct.aspx?category_path=1_4&product=3253&view_selection=Tutorials

[alfienoakes]

Cheers bdonay,

 

Nice tutorial..but I only have Vray free.. and you don't seem to get anywhere near the same amount of controls when you use photometric lights..

 

Is there anyway to get a similar effect with vray free...?

 

Andy

[Jason Matthews]

Hi Andy. Check to make sure that the cabinet is not excluded from the light. I'm not sure what it could be. I have noticed with Vray Free having a piece of glass dramatically reduces the amount of light in a space. I think you have gone about it in the correct way by adding additional lights. The materials play a great role in the lighting because the reflectance of each material is taken into account, just like radiosity. Are your materials pure white? Just add in your materials and it should fix the problem.

 

If you will not be looking at the window in the image I would advise that you turn up the enivonment higher and leave the other settings alone. Try to give yourself one variable to control instead of many.

 

One last thing, add a white plane under the model to give the light something to bounce off of into the space.

 

Keep posting. I would like to see where you take it.

[olias32]

andy here's another idea: i use a vray (area) light that i place outside the window pointing inside. i match its size to the window (maybe a little bigger) and that really brights up the scene. also you can play around with color mapping (exposure control of vray) and turn up a bit the dark muliplier.

 

cheers