metal is very easy and requires only three steps:
Step 1: Creating
a new texture
Open the New Texture Dialog
by pressing thebutton
(upper left corner) or selecting the File->New menu item.
Change the Width and Height
values to 256x256 pixels.
Set the Background Color to a light gray likeRGB(192,192,192).
Press the OK button.
Step 2: Adding
Select the function
Press the Reset button at the Presets
Panel to load the function's default settings.
Set the Direction Angle
to 0° with Full Radius by clicking on the right
Click with the left mouse button on the texture to add the
Step 3: Smoothing the
the function Filter/Motion Blur.
Load the function's Default
Preset. The Direction
Angle should now reside at 0°.
Click on the texture to smooth along the scratches. That's it.