how to make skills and their animations in opengl ? are skills 3d model or 2d?

1)slash effect 2)area skills like dota2 crystal maiden ulti and first skill 3)over an enemy skills example dota2 crystal maiden second skill

how they make in opengl

i know opengl billboards way and texture atlas i can make basic flame effect with using these 2 way together. But how they make others ? area skills are 3d model animation ? then its texture is changing every frame? over an enemy skills can 3d model i think? how they make skills transparent ? with glblend ? what is best way to make them sorry for bad english i searched but i couldn’t find any suggestion help please im using c++,sdl,opengl

I think you have to have a proper gaming engine for these…

but what main idea these techniques

like this video area skills 3d model ?

like this video area skills 3d model ?[/QUOTE]
They’re just translucent textures.

The main thing about translucency is that you can’t rely upon depth testing. You either have to render from back to front or use techniques such as depth peeling or linked lists of fragments.