It's because of the amnesia assets. Their normalmaps(I think) use a different system than the one used in SOMA. If you want to use amnesia assets you probably have to find a way to convert them to the same type of normals SOMA uses. This issue should not be present with SOMA assets.

Thanks Draugemalf, I had a look into the issue of the normalmaps and it is in fact the cause of the issue. accoding to this link (https://wiki.frictionalgames.com/hpl3/community/editors/troubleshooting#my_lightsshadows_cut_off_linearly) a 'blank' normal map was provided in the game directory however when I apply it to the floor texture in the material editor it illuminates the entire thing (ie the floor appears completely lit up irrelevent of any light sources.)

I also tried generating a new map for the texture with gimp however this yielded the same issue as before. I assume this is because the map is incorrectly formatted, however I have no idea what the correct format for HLP3 is. Is there some doccumentation that can put me in the right direction? A rudementary google hasn't helped.

@Maverick I don't know that much about normalmaps but you can ask around in here: https://discord.gg/sXKZ9R2 , some people there know more about this issue.

Alrighty, I'll give that a go when I next get the chance

Just so you know, this isn't just the Amnesia assets. It happens with SOMA assets too. I'm not sure if this has to do with the normalmaps, but I think it's just the way your computer processes them.

When I use HPL2 it works just fine but for some reason HPL3 (soma) doesn't.