Create a BP character, called Parent unit class
Reduce capsule size to 30, 10
Add decal component, called SelectionDecal
rotate Y 90 degree, and reduce size to 10, 20, 20. move it down to bottom of capsule
move down with Z axis -30, not 20 (or else won’t see the decal when put in scene)
Choose the mesh, untick Receive Decals (to hide the decal)
R click on the parent BP, create child BP class, called Unit_style_1
open it, change the mesh, scale down, and rotate Z -90
Duplicate style 1, name as style 2.
change another mesh different from style 1
Drag style 1 and 2 BP in scene
Create new material, called Selected_Decal_MAT
Change Material options as follow
Hold keyboard 3, L click to create 0,0,0 node, change to green color
Click apply
drag the material in scene, scale down as follow size (to test how material visually looks, delete it after test with the MAT graph below)
Modify the MAT as below in graph:
Linersine node is to let time (3 sec) runs value between 0 and 1 (for flashing effect)
Back to parent unit class BP
Selection decal component, change the material to what created
Now the decal is seen flashing in scene on the characters.
To make decals only visible when the characters are selected:
go to Parent unit class → SlectionDecal, untick visible
Change anim class on mesh of unit style 1 and 2