Decal floats above surface when viewed from medium distance

[hypersapien]

I’m having an issue where a decal seems to move/float slightly above it’s actual Z position and occlude objects that are actually higher than it, as soon as the camera moves ~5 meters away. It’s a little hard to put into words but I’ll do my best, and attach images to show.

There is a ground plane, Z height : 0
A flat piece of geometry at z height: 0.1cm This geometry has a decal material applied to it (ie, it is not a ‘decal actor’).
There is a static mesh (square stone slab) which is 4cm tall which sits on the ground plane and intersects the decal.

When Close, the image appears as intended. But as soon as the camera backs up more than 5m, the decal appears to rise above the height of the stone slab.

What is causing this and how might I remedy it? I checked the wireframe viewmode to verify that the stone slab isn’t being LOD’ed to a flat plane, so the problem seems to be the decal object/material.

[ClockworkOcean]

Apparently, it’s a ‘feature’ to stop Z fighting. If you turn on flat tessellation in the material it should go away.

Or possibly:

Decal draw distance

[hypersapien]

Thanks for the explanation. The flat tessellation route didn’t fix the problem, however I simply turned off “receives decals” on the stone slabs that were being occluded and that resolved the issue well enough for my purposes.

I’ll leave the post unanswered for now, in case someone knows a method to improve the accuracy of the depth tracing (?) for decals.