Sun light with photometric lights?

[RevitGary]

My client is insisting that the spaces I am currently rendering be lit with sun light streaming in and spotlights through out the interior on many objects.

 

I know this ends up looking unnatural but it is what he wants.

 

I guess my question is what is the best way to do this? I have been setting up my sun as usual with physical scale set to physical units then cranking my lights to unrealistic levels.

 

Would it be better to user unitless physical scale?

 

or does anyone have a better suggestion?

[BrianKitts]

I do unitless and just crank em up.... 300,000 if need be.

[RevitGary]

Why unitless? what is the difference?

 

I also have some inside night scenes of the same model.

 

So I am thinking keeping physical units is best for when I do the night shots.

With different lights set at real levels.

[BrianKitts]

it doesn't matter either way you'll get the same result / rendertime.

 

I think it's just a mental thing for me.... no sense in having it be in a physical unit, if it's an unrealistic value.

[Justin Hunt]

Rather turn the sun down and use realistic settings for the photometric lights. In this case the sun should be considered as secondary light and the photometrics as primary.

 

I have found that if you are combining sun and photometric lights, you get more control if you use photons. Then dial the suns photon energy values right down and the photometrics right up.

 

jhv

[RevitGary]

Justin thanks sooo much your post really sets a lot of things straight for me.

With the help of this board I have gotten reasonably good with this stuff.

I keep pushing to get better.

 

It seems the settings you have would give you realty long render times?

 

Let me ask this, if you were to do this with a much larger scene 25' ceilings glass on 3 sides to the outdoors a skylight portal.

How would you change your GI settings? I would think you would greatly increase your sample radius 250 mm?

Also would you decrease your GI photons per light? Decrease trace depth to 30, 30, 30? are these reasonable adjustments for a large scene?

[Justin Hunt]

I might increase the radius, although I'd leave the trace depth. If you increase the radius then you will need to increase the samples too. It also depends what is going inside the space. If its a reletivly empty space then I'd use a large radius, but if there is alot going into the space and light detail is important then I'd leave the radius small.

 

With regards to render time, dispite shooting a shed load of photons the calculation time was kept down but the low samples. The low FG settings and high interpolation samples keep things smooth and quick to calculate. The acutual rendering wasn't too slow either.

 

There are two ways to deal with photon radius,

1) Use a small radius, really low samples and lots of photons

2) A large radius, lots of samples and fewer photons

 

Benifit of methode 1... more accurate and detailed indirect lighting.

Downside of Methode 1 .... Uses alot of memory , can take longer to calculate Photons

 

Benifit of mothode 2 ... Quicker to calculate and uses less memory

Downside of Methode 2 ... Alot more samples are needed to get accurate light detail, lighting can be over bright as the solution gets smoothed out.

 

jhv