Lighting problem [Mac]

I am currently testing UE4 on a Mac at my college, but there are these strange lines where light is being cast onto surfaces. I’m currently wondering if this is just an issue of the Mac not being powerful enough. If anyone could help with this it would be much appreciated.

  • iMac, Mid 2010
  • 3.06 GHz Intel Core i3
  • 8 GB 1333 MHz DDR3
  • ATI Radeon HD 4670 256 MB
  • OS X 10.9.5

We haven’t done much testing against the old ATi 4xx0 series cards on OS X, but that looks like an ATi 4xx0 driver bug to me (I’ve seen it before in other non-UE4 games on that GPU). I’ve filed a bug in our system for this: [UE-5732]. You should try updating to 10.10.1 to see if it has been resolved in a driver update though I suspect it is unlikely for that GPU.

This bug has been fixed for 4.7 - if you are willing to build from github source yourself, check out the UE4 version you were working with and apply git commits:

  • b12ef89f68ff3062ddccb4135b1cb2d59b4e700a
  • deb91d41b4d3031beaab9686265bc39877d882b1