Outline objects using no Post Process Material

Is this possible?
Since using post process effects is costly for standard mobile devices… it is possible doing this using something on the material of each actor?, or maybe find another way.


Using the classic inverted object method should work fine on mobile.

In your modelling application:

  • Create a copy of the object
  • Move the vertices a little bit along their normal (Max has a push modifier to do this, other tools probably have something similar)
  • Invert the normals

In Unreal:

  • Apply an unlit shader with your outline color to the object
  • Link the outline object to the base object

You could also consider doing the offset in the vertex shader to allow for line thickness control in the engine.

It is possible to invert normals from unreal?

In UE3 you could do that by inverting the normal. In UE4 this only influences the lighting, but won’t actually invert the surface direction. My guess is that this is incompatible with the deferred renderer. So you’ll have to do it manually.

One advantage of doing it manually is that you can also remove all hard edges and UV seams, reducing the vertex count for the outline model.