Blender Relief Tutorial: The Sun

Previous Chapter: The Camera

In Blender, light sources are called lamps — again, think of a photography studio. The color, type, and position of a lamp affects the scene’s lighting, and thus the final image.

Choose Lamp Type

Our default scene comes with a lamp in it already, which looks like a couple of dashed-line circles with a dot in the middle.

LampSelect.jpg

Seen here selected in orange.

In the 3D view or the Outliner, select the existing lamp. Then, click on the yellow icon that looks like a lamp with arrows coming out of it to look at our Object Data Properties.

LampIcon.jpg

Here we can specify a few things about our light source. Under the Lamp set of options, I see a number of different lighting types: Point, Sun, Spot, etc. Right now, Point is selected. This means that our light source is basically going to act like a light bulb, floating above our scene and casting light in all directions. We’ve also got options here for analogues of other real-life types of lights, like spotlights. For making shaded relief, though, we want to simulate the Sun, so choose that one. Notice also that the icon to get to this panel also changed.

SunChosen.jpg

A lightbulb near you will cast light rays in all directions. The Sun, on the other hand, is far enough away that the rays of light that reach Earth are practically parallel (at least, when considered over a modest-sized area). That’s what we’re telling Blender to simulate by choosing this option. It will flood the scene with light rays all coming from the same direction.

Rays.jpg

Light rays are pretty much parallel as they strike the Earth.

Set Sun Angle

The next thing to do is tell Blender what direction the light is coming from. And to do that, we need to go to a familiar place, the Object Properties. While the lamp is still selected, click on that orange(ish) cube icon.

BackAgain.jpg

Now, when we went here for the plane and for the camera, we adjusted their positions. It turns out, though, that with a sun lamp, we don’t care where it sits on the stage. Blender ignores the lamp’s position entirely and simply hits every part of the scene with parallel light rays of equal intensity. The only thing it cares about on this panel is what angle to give the light. Notice how there’s a dashed line coming from the lamp in the 3D view: that’s the current direction of the light rays.

CurrentAngle.jpg

The current angle of the rays upon our plane.

We can change that by changing the lamp’s Rotation in the Object Properties. Enter 0 for X, 45 for Y, and 135 for Z. Notice how the dashed line changes; now the light will hit the scene from a different angle. Have a look at how it’s turned out by rendering a new relief.

GoodAngle.jpg

It’s looking much better now that we have the right sort of light source (though, as ever, there are still some things to adjust). Try changing the Y and Z numbers on the lamp’s rotation and doing renders to see what happens. The Z number controls what direction the light comes from. 135 means upper left. 225, on the other hand, means it comes from the lower left. As a general rule (for all shaded relief methods), light should come from the upper left of the scene, or the relief will start to look inverted.

InverseAngle.jpg

This was with a 315º angle: light coming from the lower right. Many people will see this as inverted, or at least confusing.

Changing the Y number here will affect how high the Sun is in the sky. Notice if I crank the Y up to 75, the dashed line in the 3D view shows that the light rays will be closer to parallel with the ground. That would simulate the Sun being lower in the sky, near dawn or dusk.

LowAngle.jpg

Let’s keep things at 45º and 135º for the time being. You’ll probably have occasion to change the former much more often than the latter.

Sun Size and Strength

Now, go back to the Object Data Properties by clicking on the Sun icon. There are a couple other things to look at. First off is our Sun’s size. This controls how soft the shadows are. Right now the sun size is set by default to 0.1. This is very small, and we have a very harsh relief that looks sort of like we’re on the Moon. If I instead set the size to 1, the shadows will become much softer.

SunSize.jpg

Feel free to play around with this setting and do test renders.

CompareSize.jpg

Sun size 0.1 on the left and 1.0 on the right.

I generally keep this setting at 1, though if you were doing a Moon relief I suppose you might want to lower it.

Finally, we want to adjust how bright the Sun is, which affects how light our relief appears. We can only get that option to appear if we first click the Use Nodes button, which then shows a couple extra options, including Strength. That’s the one we’re interested in. The higher the number, the brighter the sunlight and the lighter the relief. You can play around with this setting, but I usually set it to about 3.

Brighter.jpg

With a brighter sun, the relief is not only brighter, but it has more contrast.

There’s no need to change the color of the Sun here. It’s white, and that works fine for our greyscale relief. If you want to do relief in color, you might try messing around with this (and with the color of your plane material).

With that, our lighting is ready for the scene. We managed to

  1. change our lamp type to Sun,
  2. set it to the correct angle,
  3. increase its size, and
  4. increase its strength.

Just a little bit more to do and we’re all set!

Next Chapter: Final Adjustments

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