How do I add dirt or grunge onto materials?

okay not real sure how to ask this, but here goes, our entire level is meant to be old and quite plainly dirty, if there a simple way to make a “dirt” texture or “grunge” texture that could then be applied to any material and adjusted in the material editor to apply a “dirtiness” to any material, be it furniture or walls and floors, i know this feature was easy in cryengine and i assume ue4 has an ability to do it also, any help highly appreciated

A good approach for this would be using Unreal’s new Layered Materials system. You could make a couple of different dirt/dust materials and for each object you could make a mask, and within a layer material blend between the two.

Here are some links:

Another good method would be to use Vertex Painting with your meshes. This documentation should get you started with that as well.

It’s not too dissimilar than setting up a landscape layered material that you allows you to paint areas of the mesh with different textures.