Ground Cover Foliage Lighting

godejon · Mar 2015

Hi all! First post, first(ish) project. Can anybody point me in the direction of a general explanation of how to get UE4's lighting to work well with foliage objects (double sided planes spread with foliage tab)? I've been fiddling with settings for quite a while now, but I really have no idea what I'm doing. (I know the trees have numerous problems, but I want to work on the ground.)

Here is 2 shots of the scene, if they help at all.

Here is the inspiration.

It seems like the problem is that there is only one level of shadow, so it makes everything seem really flat. All the ground cover object's normals are pointing straight up.

I think it would take a while for me to show you every setting and material I have - I really want to understand, rather than fix what I have. I'm looking for a faster way to learn than fiddling, but if fiddling is the best way, then I will fiddle on.

Cay · Mar 2015

did you build lighting?

Bedrock · Mar 2015

Is it still necessary for the normals to point upwards? I've viewed someone's grass example and it looked great (without normals pointing upwards) in 4.7. I've also tested it and had good results. I guess it's pretty easy to try though, just recompute normals (or tangents idk) within unreal 4 and just re-import if it doesn't look good.

alecchalmers · Mar 2015

Did you create the double-sided planes yourself, or did you check double-sided in Unreal? I remember an Hourences tutorial a while back that said double-sided sometimes messes up your normals if you tell Unreal to deal with it.

teaandcigarettes · Mar 2015

godejon wrote: »

It seems like the problem is that there is only one level of shadow, so it makes everything seem really flat. All the ground cover object's normals are pointing straight up.

I think it would take a while for me to show you every setting and material I have - I really want to understand, rather than fix what I have. I'm looking for a faster way to learn than fiddling, but if fiddling is the best way, then I will fiddle on.

Most likely it is normals that are causing this problem. Having normals that point upwards makes sense for grass, but for plants like these, it will remove any shading such mesh might have. I would reset the normals to their default state. Once you do that, if your shading looks too strong or too contrasting, then the right solution would be to apply some sort of translucency to the material.

Adjusting vertex normals on foliage is really an old school hack, that should be used carefully in PBR engines. For example, in CryEngine (where I have most foliage experience) changing your normals will mess up fresnel and gloss calculations.

Ground Cover Foliage Lighting

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