During an experimental session at university me and a friend ran into issues. We were experimenting to test that translucent (alpha) objects should be more expensive to calculate than objects that are masked with opacity. Although when testing this in UE4 it does not seem to be the case. Translucent materials seem to be calculated much quicker even if there is multiple meshes stacked with translucent materials. This seems to go against what we have learnt in theory. Here are some screenshots we took with different blend mode materials.
Opaque:
Translucent:
Masked:
Here are some images of shader complexity. (In theory masked should be less red as it doesnt have to draw pixels behind other geometry)
Masked:
Translucent: