Sacrament burnt my retinas

arks0ng

So I grabbed these sets yesterday; Sacrament Iray Addon | Daz 3D Mortis for Sacrament Iray Addon | Daz 3D (And obv the original Sacrament set too)

They're nicely made, as is the rest of the stuff by the PA, but upon loading them my screen was pretty much entirely white. At first i thought I'd messed up my environment settings (or maybe the church was filled with some kind of divine holy light), but after some poking around it seems that the chandaliers load with a luminace level of 750 KCD/m^2

Just one of those babies is enough to blow an entire town's power budget, and these cathedrals have about seven of them. So for anyone else that might experience this in the future, I found manually changing each down to cd/m^2 in the surfaces tab did the job quite nicely. Bit of a pain with so many, but I guess you can save some presets.

I wonder why this might be the case. Is it something to do with the recent daz updates? Could my settings be funky and automatically applying those values? I find it hard to believe this is how the products came out since presumably someone would've made a post about this by now.

WendyLuvsCatz

probably made for a different  build

Nvidia changed lighting D|S4.20

benniewoodell

The new Nvidia driver update also changed things. All my HDRIs after updating a couple of days ago, I have to half the environment intensity to make it match close to where it was before the new driver. 

Expozures

I did some experimenting a little while ago with lighting.  One common theme I see over and over again is about cranking the lighting to like 100,000+cd/m^2.  This seemed insane to me that Daz would work like that.  A standard 100W lightbulb has a luminance of around 1800cd/m^2 (which is what Daz defaults to).  With the law of inverse proprotional, this means at 2m, the light should be 42 lumens, at 3m, 6 lumens, and so on.

Placing a spherical light at 1m away from the model set to the default 1800 lumens, should be enough to properly illuminate the model...though, keep in mind, with Daz, we are working in a void.  In the real world, we have a lot of ambient light as well...even on a moonless night, the stars would still provide a little bit of ambient light.  In Daz universe, there are 0 light sources other than what we introduce.

But, that said, putting the model inside a 3mX3m box, with a 100W light 1m away from the model, and the camera positioned 2m away from the model should provide enough light to illumiate...yet, for some reason it doesn't seem to.

But, taking a look at the world of photography, where a photographer has much less control over light sources than in Daz (see above with ambient light coming from everywhere), what the photographer does have complete control over, though, is the camera settings.  And Daz provides us with those as well, under the tone mapping setting.  By referencing photography charts, and setting the aperture and shutterspeed to what's acceptable for an object lit with a 100W light bulb...you get the same results as leaving the tone mapping settings at default, and cranking up the light source to 100X that of the sun.

Though, this is exactly what an off-camera flash does.  It pulses a light for 1/1000th of a second at 15W (which works out to around 150,000 lumens)...since, in the real world a person would melt if exposed to 150,000 lumens constantly.  Though, our models don't feel pain or heat, so we can crank on that 150,000W bulb and leave it powered on while we fiddle with our model's clothes or hair to make it look just right.

I guess the point is...if you want your lighting to be realistic, set it to realistic levels.  If your model is holding an actual candle, the candle itself should be giving off 1cd/m^2.  Adjust your tone mapping settings accordingly, just as you would in the real world.

Expozures

Expozures said:

I did some experimenting a little while ago with lighting.  One common theme I see over and over again is about cranking the lighting to like 100,000+cd/m^2.  This seemed insane to me that Daz would work like that.  A standard 100W lightbulb has a luminance of around 1800cd/m^2 (which is what Daz defaults to).  With the law of inverse proprotional, this means at 2m, the light should be 42 lumens, at 3m, 6 lumens, and so on.

Placing a spherical light at 1m away from the model set to the default 1800 lumens, should be enough to properly illuminate the model...though, keep in mind, with Daz, we are working in a void.  In the real world, we have a lot of ambient light as well...even on a moonless night, the stars would still provide a little bit of ambient light.  In Daz universe, there are 0 light sources other than what we introduce.

But, that said, putting the model inside a 3mX3m box, with a 100W light 1m away from the model, and the camera positioned 2m away from the model should provide enough light to illumiate...yet, for some reason it doesn't seem to.

But, taking a look at the world of photography, where a photographer has much less control over light sources than in Daz (see above with ambient light coming from everywhere), what the photographer does have complete control over, though, is the camera settings.  And Daz provides us with those as well, under the tone mapping setting.  By referencing photography charts, and setting the aperture and shutterspeed to what's acceptable for an object lit with a 100W light bulb...you get the same results as leaving the tone mapping settings at default, and cranking up the light source to 100X that of the sun.

Though, this is exactly what an off-camera flash does.  It pulses a light for 1/1000th of a second at 15W (which works out to around 150,000 lumens)...since, in the real world a person would melt if exposed to 150,000 lumens constantly.  Though, our models don't feel pain or heat, so we can crank on that 150,000W bulb and leave it powered on while we fiddle with our model's clothes or hair to make it look just right.

I guess the point is...if you want your lighting to be realistic, set it to realistic levels.  If your model is holding an actual candle, the candle itself should be giving off 1cd/m^2.  Adjust your tone mapping settings accordingly, just as you would in the real world.

Sorry, my maffs is wrong.  A studio flash is 50W@1/1000th second, producing an effective 30,000 lumens.  And for reference, the sun emits 127,000cd/m^2

AlmightyQUEST

I do think Studio's numbers are weird, but where did you get that value for the sun? That's... wildly off?

Expozures

AlmightyQUEST said:

I do think Studio's numbers are weird, but where did you get that value for the sun? That's... wildly off?

https://en.wikipedia.org/wiki/Daylight

The amount can vary on conditions.  120,000 is the max that we experience.

AlmightyQUEST

Ok, the surface illuminance is around 120,00, that's not what the sun puts out. A 60 W frosted bulb would be putting out around 120,000 cd/m^2, but that's not what a surface at some distance away is going to see. We're talking about it from different directions, it was the "sun emits" that had me confused.

 

**I am forgetting my terminology. We are talking about luminance versus illuminance, my understanding has been that the lights in Studio are setting the luminance.

arks0ng

benniewoodell said:

The new Nvidia driver update also changed things. All my HDRIs after updating a couple of days ago, I have to half the environment intensity to make it match close to where it was before the new driver. 

Huh, that's interesting. If it's the latest update then we have the same one, but I often find myself increasing the environment intensity several times over. That said, I'm usually doing scenes indoors and like a lot of stylised light blasting in the windows. 

It's sort of a pity that so many products can completely change (or even become unuseable, re; ghost lights earlier in the year) as the tech changes. Sometimes PAs do updates, but more often than not I'm just having to hope a product still works as intended and trust daz would remove it if it didn't (I know, I'm foolish). Still, that's why we link and create these little posts, I guess