How to create Faux Doors?

[Neona032]

I've seen some people create a faux door frame like this to make it look like there's a room in the background you can't get to. Does anyone know what blocks/paints/techniques are used to get this effect?

 

[Green_Metaknight]

Probably some sort of curved block like the balloon block that's been shadow painted and actuated.

 

[Neona032]

Ah yup, just tested it and that was it. I couldn't figure out the curved corners on top
Thanks.