Can Normal map detail cast shadows or faked shadows?

OccultMonk

When light falls at a glancing angle even smaller Normalmap details will cause cast shadows. Is this possible or is there a way to fake this effect? 

poopipe

without height information there's no way to do it and have it look anything but shit.  

i believe the parallax occlusion mapping implementation in unreal does shadowing  - its expensive though

FlorianSchmoldt

Check for "Bent Normals". They're close to standard normal maps but use modified R and G channels to fake soft shadow occlusion

OccultMonk

Thanks!

parallax occlusion: Would this work in a scenario where it is only used when up close to the objects? So fade the parallax in when you are at a certain distance. I mean does it also have a performance impact when it is disabled due to distance?

FlorianSchmoldt It's mostly for microsurface detail with a tri-planar mapped Normalmaps. Do bend normals also work on microdetail normal maps or only on baked tangent space normal maps?

OccultMonk

Does anyone else know if parallax occlusion or bend normals actually work for tiled tri-planar mapped normal map details to create cast shadows on micro details. 

poopipe

bent normals will work at any resolution  - assuming you have the texture resolution to support it. you wont get sharp shadows though.

you can certainly use POM in a triplanar mapped material but you're looking at a fuckload (technical term) of texture samples - tessellation would probably be cheaper 

I'm not sure if the default unreal stuff will allow you to plug it all together - I can't see any reason why it wouldn't though

OccultMonk

Tessellation is currently not supported in UE5.

poopipe

not at all ? or just on nanite meshes. I've not checked

any reason you don't want to use nanite for this? 

OccultMonk

Basically, because I want more customization, and because I need extremely small details.

Tessellation is not supported currently in UE5 I believe, only heightmaps for landscapes or something.

poopipe

I'd wait tbh they'll either put it back in or come up with something better before long.

if you're not bothered about performance then POM should work in the meantime 

OccultMonk

Can you use 'fade out' Paralax Occulsion Mapping at a distance, so it only has performance impact up-close? Or does it stay active even when you use a distant blend?

poopipe

you'd have to profile it to see whether the clever bits are getting chopped out but in principle it should work.  it's just a pixel effect 

Andrew

This method might work for you, it's mostly only useful if it's being lit by a sunlight or 1 main light direction: https://answers.unrealengine.com/questions/86285/help-self-shadowing-materials.html

poopipe

i suspect POM would be cheaper tbh