1B-3: Daylight Set Up

Unlike in real world, you can control the lighting of your 3D scenes. It's quick and easy and something you should thoroughly take adventage of to show your project in best light - pun intended.

Daylight set-up refers to setting the lighting conditions of your model in such way to simulate the lighting coming from sky and Sun. Most software programs, Rhino included, come with tools to directly address this task, and we will take a look at these tools. We’ll end up taking a look at how to do these tasks manually, which is slightly more complicated but gives much better control over results.
But before we start, a bit of “theory”.

Difference Between Sun And Sky

By this title, I don’t mean getting into physics, nor some poetic metaphor. This simply refers to the fact that Sunlight and skylight will affect your 3D composition in very different ways, producing very different visual effects. To put it simple:

Skylight is soft and used reveals the form, sunlight is sharp and used to ‘design’ shadows.

Here’s an explanation that I lifted directly from another tutorial I made on the same subject:

 

Skylight

Sky will give us nice soft shadows that help see the shape of our objects.
Skylight comes from all sides equally, and that is why it results in such a finely detailed lighting. In real life, this is the result we get on a day which has a thin layer of clouds overcast.

sky-only2
Rendering a scene using skylight only: we can clearly understand the 3D form.

Sunlight

On the other hand, sun light is very sharp, coming from one distant point, and usually doesn’t light up very much, but it provides a good contrast:

sun-only2
Scene lit by Sunlight only.
Note that sun was positioned to create a shadow that looks visually good in this composition (diagonal)

By using Sunlight only (which is a condition that in nature exists only outside of Earth atmosphere) we don’t reveal much of our building at all, but we have an opportunity to use contrast to add more dynamics to the image. In other words, always position Sunlight in such way that the shadows look good – think of Sunlight as a purely graphic, 2D tool. Of course, make sure that the general direction of the Sun would be possible in real world (ie. if your project is situated on northen hemisphere, Sun will never come from the North – and vice versa).

Sun + Sky

Now let’s take a look at how these two look together:

sun-and-sky2

It’s skylight that actually let us see the space, especially areas in shadows (which would be completely black as in the previous image). However, Sunlight both add dynamics by emphasising the diagonal, as well as makes image more “lively”- otherwise it would look too cloudy and gloomy (which is sometimes ok if it works with aesthetic you are pursuing).

That was the theory, now let’s see how it’s done in Rhino.

Rhino Sun + Sky Control

Automatic Control Via Sun + Sky Panel

Rhino comes with simple to use built-in control for Sun and sky.

It has its own panel which is called via Sun icon in Render Tools toolbar.
Take a look how to open and use these controls to turn on/off Sun and sky, and move Sun either manually (which I advise) or via calendar control (not displayed in video):

Play around with these to achieve the results you like. Very likely, though, you will notice that the Sunlight is too bright and burns out the image, so it would be nice if we could change the intensity (or even color, like in real world) of the Sunlight.

Changing Sun Intensity And Color

Unfortunately, Rhino doesn’t let us change the color of either Sun and Sky, so we need to revert to alternative (and more complex) ways to get these results.

In order to control Sun color/intensity we need to turn it off and then simulate the Sun by creating a Target Directional Light.

As Rhino’s built-in Sun doesn’t cut it, we need to turn it off and create our own Sun. Rhino has different types of lights you can add to scene – the one that best emulates Sunlight is called Target Direction Light.

Take a look at how to create one, and move it around.

As you will notice, when you select the Target Direction Light icon, Rhino will first ask you to click on your model to determine where the target of light is (where the light points to) and then to click again to pick the light position.
Ideally set the target somewhere near the center of your model, and move the light around it without moving the target.

Setting the color and intensity.

Click to select the light (if it’s not already selected) and take a look at Properties panel. There you can change light color and intensity:

This fakes our Sun burn-out.
For this particular exercise (1B>Rhino Safari) we want Black/White images, but why not playing around to see if you can add a bit color to Sunlight to make it more realistic.

This pretty much is enough information for you to finish this task.

Related Tutorials

If you want to learn more about creating more realistic lighting, especially using color for sky and Sunlight, take a look at this tutorial. It’s similar to this one, but then goes into much greater detail:

Rhino #4: Lighting Set UpAfter we have defined our cameras and views, first step for creating convincing images is setting up scene lighting. Here's how to do this in Rhino.

 

 

 

 

Any questions?

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