Unreal Crash When Landscape Material Uses Opacity Mask

I have created a landscape in UE 4.13 to use a material with a landscape visibility mask for holes in the landscape, but plugging anything into the opacity mask node and then attempting to paint the landscape causes Unreal to crash with the following error:

Breaking the link to the opacity mask makes everything to work perfectly fine (except no holes, obviously). I have tried this with multiple landscapes and materials and only the most basic one works (nothing plugged in except opacity). All of this worked before UE 4.13.

Hi iknifaugood,

I took a look at your callstack and found that it is directly caused by this. I’m happy to report that this has already been fixed in an internal build and the fix will be in the 4.13 release.