Sparkles from asset store normal map.

Hello,

I am using some assets that I got from the Unreal asset store and am noticing that I am getting some bad sparkling happening that seems to come from the normal maps.
I have tried using just the normal map and not connecting any of the other asset textures and still it shimmers strongly.
This effect moves and sparkles if I move the camera view point and it is still there if I move further away from the asset.

Here is an example of how it looks with default shader and just the normal map,
sparkles.png

Does anyone know what this problem comes from and how I can get rid of it?

Cheers

Try changing the normal map compression settings. And if the texture is too small, don’t use too much detail on it. There is also a chance of it being cause by texture padding when generating the normal map.

The texture is of good size for the object and certainly for the area I’m looking at. And the artefact happens far from the edges so texture padding shouldn’t have anything to do with it.
I have tried a few different compression presets but when they are not ‘Normal Map’ then the output changes values. For example if I try HDR which doesn’t compress the channels (I think) then the out normal map values are all washed out desaturated. I can approx the old output values by doing pow(5) but that’s not accurate. Anyways even with that compression I get the artefact just in a different place.

EDIT: I just found the cause it’s coming from a point light that has non zero in its ‘Source Radius’ value. I also get the artifact when ‘Source Length’ has non zero value.
Which is strange as these should in theory make highlights broader and not infinitelly small as that artifact seemed to be. I wonder if it is some kind of bug.