For example, is there a way to spawn a “snow” material and project/overlay it on my landscape at runtime, without effecting any other actors? I’ve seen the decal option, but it seems to have serious limitations about how it’s used (it can’t exclusively be painted onto the landscape, as far as I know).
You can add snow texture in your landscape material, and think about some sort of a mask, to control where snow appears. You can control intensity of the snow using Material Parameter Collection. For a mask, you have multiple choices. For example, pre-painted mask,or a texture, that was exported from software, that you used to create your terrain. Alternatively, you could define, where snow spawns by height and slope of terrain. You can use combination of techniques. In case, it is landscape material you should be looking at to achieve this effect.
I don’t currently have access to change the landscape itself prior to executing the blueprint code, that’s why I was asking about changing the materials at runtime. Thanks for your input, though.