Heavy math for parallax depth
The greeble texture is resembling mecahnical details of classic scifi ship designs.
Set its depth and selfshadowing to achieve enormous detail even on low poly meshes.

Complex layering for versatile realism
The greeble textures also have small windows, which are lit,

so that even in dark scenarios there is enough plasiticity to see the shape of your ship.

Panels cover the greeble according to mesh curvature and normals dynamically.
Adjust the masking with one slider to your pleasing. 

As final touch the parallax depth generates selfshadowing,

so that even low poly meshes score with realistic detail-shading.

You can set the direction of this fake shadow, in order to match your sunlights direction.

weathering and dirt

According to the textures and mesh data you can add dirt onto the surface,
leading to an even more realistic and used look.

customize with your own textures

You can use your own greeble texture with their displacement and emission!
The according nodegroup is located right next to the shader in the node editor for quick access.