- Qt 3D Studio
- Best Practices
- Motion Blur
- Qt 3D Studio 2.8 Manual

# Motion Blur

The motion blur effect takes the image from the previous frame, blurs it, fades it by a specified amount, and draws this in the transparent areas of the layer. The result is that items moving over a transparent background leaves a ghost behind them.

## Properties

Property | Description
--- | ---
Fade Amount | The amount the trail fades. A value of 0 does not fade the trail at all. The trail is permanent. A value of 1 fades the trail completely, more or less omitting the motion blur effect.

## Usage

When using this effect, you should be aware of the following caveats:

- The contents are slightly blurred, which (as shown in the image above) can cause static (and even slowly-moving) items to have a halo around them.
- Only the transparent regions are drawn to. If a moving object passes in front of another object on the same layer, there is no motion trail passing over the object.

In the image shown above the blue ring is placed on a second layer underneath the layer with the motion blur effect applied. This both allows the needle to leave a blur trail over the ring, and also prevents the ring from having a blurry blue halo around it.