How Displacement scale actually works in blender?

Hi. In this video, you can have a quick look at what displacement node value is best.

More details are in the article below.

Not everyone may understand what Displacement is. In simple terms, Displacement is a dent on the surface, as if we were pressing soft clay with the palm of our hand.

So the Displacement Scale is the force with which we push the clay. Only in a blender we can press not only to the depth of the surface but also to the opposite side.

To understand how the displacement node works we need to deal with some of the material settings.

The first way to display Displacement is "Bump Only".

The second way to display Displacement "Displacement Only"

And finally, the last and most resource-consuming method "Displacement and Bump"

So if we use the "Bump Only" method. Then there is no actual "extrusion" of the surface. That is, the plane remains a plane, but dents and convexities do not appear on it. These changes remain "virtual" and we can see the changes on the surface only with the help of shadows. Often this is more than enough for a reasonably realistic image. It's the easiest way for the CPU to make calculations because there is no actual change in geometry and the plane remains a plane.

Nevertheless, the Displacement setting is still an important parameter, because it determines how accurate the shadows will be, and how visible will be all the irregularities on the surface.

It's good to remember that the Displacement scale= 1 is equal to one meter of extrusion. In most materials, the surface rarely changes that much. Typically the Displacement scale ranges from 5 centimeters to a couple of millimeters, that is from 0.05 to 0.001. Below you can see examples of how the shadows change in real-time depending on the Displacement Scale.

You can find the Displacement node in the Shader Editor

In the example below, you can see how the shadows on the surface change when you change Displacement scale from 0 to 0.1 or from 0 centimeters to 1 meter.

Notice how near the end of the animation there is distortion and black dots on the surface of the bricks, cos of excessive Displacement scale.

Below are more examples of surface visualization with different Displacement Scale from 0.01 (1 centimeter to 1 meter)

• Displacement scale 0.03 or 3 centimeters - Soft, correct shadows without distortion or artifacts.
• Displacement scale 0.1 or 10 centimeters - Shadows are harsh, artifacts start to appear.
• Displacement scale 1 or 1 meter - Shadows are harsh, artifacts and black dots all over the place.

To explain the displacement scale even more clearly, let's turn to the option in the material settings

"Displacement Only"

This option works when certain parameters are activated in the blender settings.

1. You need to set the blender to Experimental mode
   

1. After that, you have to apply the Subdivision surface modifier and activate the "Adaptive Subdivision" option.

In the video examples below, you can see how Displacement scale works with the Experimental mode, "Adaptive Subdivision" and "Displacement Only"

In this video, you can see how the surface of the material changes as the Displacement scale increases from 0 to 1 (0 to 1 meter)

So, if you take it apart, it's very simple ;) Just imagine how deep the irregularities are on the material you are working with and set the Displacement scale according to these values.

Thanks for your attention and have a great day with blenderkit ;)