- [Instructor] In the last movie,
we added a physical sun and sky environment
for natural day lighting.
Now we're ready to art-direct the lighting.
I've already got active shade running,
rendering the camera view.
Let's take a look at the controls on the sun positioner.
Select that in Any View port.
Go over to the modified panel.
And we can adjust the sun position using one of three modes,
date, time and location,
weather data file, or manual.
Let's look at date, time and location first.
We have two sections here,
date and time and location on earth.
And those sections combine in order
to spit out the azimuth and altitude
or horizontal coordinates of where the sun is in the sky.
We'll take a look at manually adjusting these in a moment.
But for now, we're going to adjust them indirectly
by plugging in the date and time and location.
So we have the time up here.
Let's set that to 1400 hours, which is 2:00 PM.
And then the day, month and year.
Let's make it September
by setting the month to nine and the year 2023.
Now we've got lighting at 2:00 PM on September 21st, 2023
but our location is San Francisco, California.
Let's change that to something else.
Click on the big button here
that's currently labeled San Francisco, California
and we get a window geographic location.
We can choose a continent from this pull down list up here.
We can click anywhere on the map
in order to choose the nearest city.
So I can click down here in Arizona.
Try to click on some city there,
but I don't have a lot of resolution to that.
If I want to choose a specific city, I probably want to do that
from the list over here on the left.
And so, I'll scroll around until I find Tucson, Arizona.
Select that.
Click, okay.
And now active shade is showing us exactly
what the light would look like on a perfectly
clear sunny day in Tucson, Arizona
on September 21st, 2023.
So again, this is very useful
for architectural lighting studies.
We can also set the azimuth and altitude manually
to our direct, this a bit more intuitively.
And to do that, we would switch over to manual mode.
And now, the horizontal coordinates can be directly edited.
We have azimuth,
which is the angular value around the horizon.
And we have altitude, which is the angle above the horizon.
So let's play around with these.
We'll bring the altitude down.
Just click and drag on that spinner and bring that down.
And we can see here in our Perspective View
that we're moving the sun downward, closer to the horizon.
And we can also see our shadows are lengthening here.
So if we have an altitude of, let's say 20 degrees
then we get this golden hour effect of quite near sunset.
Now let's try azimuth.
Once again, click and drag on that spinner.
And we can rotate the sun around in the sky.
If we increase that value,
we can make the sun swing around
so that we have light coming from screen-right
instead of screen-left
with an azimuth of a 150 degrees or so.
Okay, now let's set the horizontal coordinates back
to the sunny afternoon effect we started with.
I'll plug in an azimuth of 200 degrees,
press Tab and set the altitude to 56 degrees,
and press Enter.
What we're seeing once again is the natural light
on a perfectly clear cloudless day.
If we wanted a cloudy day, we would go into the parameters
for the sun and sky environment map.
To do that.
We need to load the environment map
into the material editor to get at its parameters.
So we'll need to open the environment dialogue.
There's a shortcut for that
which is the numeral eight on the alphabet keyboard.
So click somewhere in the main 3Ds maxed interface
to give it focus,
and press the eight key on your alphabet keyboard,
not the numeric keyboard.
And we get the environment and effect dialogue popping up.
And likewise, we need the material editor.
We can open that with its keyboard shortcut, which is M.
Now we've got both those windows open.
And just as before we want to drag the environment map
over into the material editor's center panel
or view and choose instance.
We have the physical sun and sky environment map selected,
and we can start adjusting its parameters.
Now the most extreme thing that we could do here
would be to complete disabled the sun, turn it off.
We have a checkbox here, sun, turn that off.
And now we're only getting the light
from the sky and the ground plane.
And this might be helpful actually
if you wanted to provide the sunlight
from some other source, such as an Arnold distant light
that might give you more control.
But we still have quite a lot of control just directly
within the physical sun and sky-environment map.
I'll turn the sun back on again.
Let's create the effect of a partly cloudy day
when the sun is currently obscured by clouds.
We've got the disc size parameter here.
I'm going to increase that by factor of 10,
bring that up to 1000%.
And that has resulted in a much softer illumination
and much softer shadows.
If the sun is behind clouds
then, the illumination is going to be spread over a larger area
because the clouds are acting as a giant diffusion gel.
Additionally, if the sun is behind a cloud
then it's going to be less intense.
Let's the sun disk intensity down.
We'll knock that down to a value of 0.25 and press enter.
And if the sky was full of white clouds
then the sky would be brighter.
We can increase the sky intensity accordingly.
Let's bring that up to value of 1.5.
And finally, if the sun is behind a cloud
then it's going to be slightly more blue.
We can change the overall tint of the entire system
down here from this color swatch.
So click on that Color Swatch.
And let's set the hue to 170,
and the saturation to 40.
Click, Okay.
And now we've just tinted our entire scene,
pushed everything towards blue.
Now that we have less light overall,
we'll want to adjust our exposure accordingly.
So let's go back to our environment and effects dialogue
and play with our exposure value.
Let's bring that down one and a half stops
to a value of 13.5 and that's brighten it up.
We also want to compensate
for the blue light that we've introduced here.
So let's adjust our white balance.
We'll set the temperature manually
to a value of 9,000 degrees Kelvin, and press Enter.
And now we've got a pretty good effect here
at least on the actual geometry.
However, the background in this rendering
isn't really giving me the effect that I want
that doesn't match the simulated cloudy conditions
that we've created.
But in a previous movie, we saw how to deal with this.
We can easily use the background environment switcher node
to substitute a cloudy background image.
I've got a scene file prepared to illustrate that.
So let's open that up.
And go to the file menu and open.
I'm not going to save these changes.
And I've got a scene file that's labeled,
09_12 cloudy example dot max, open that up.
And in the slate material editor
we can see that we've got a very simple network.
I can navigate with the middle mouse here.
We've got a background image that is
the HDRI Environment node.
And it's got an image cloud layers, 8k.HDR.
That's providing the background.
And then we've got a physical sun and sky environment
which is providing the environment lighting.
And we can go ahead and initiate an active shade rendering
and take a look at that.
Once that's finished rendering,
we can see just how easy it is
to create this cloudy day effect.
We've set up our natural day lighting
with the sun positioner and physical sun and sky environment
and also replace the background with a Panorama image.