First steps in Lighting and Rendering

Hello everyone,

I would like to create topic here to discuss multiple problems which I would like to solve. I decided to run this tread which will help me stay motivated and posting as much as I can everyday. Also I’m keeping my fingers crossed if it is appropriate category :slight_smile: Mostly it is about lightmass and building light. I’ve started with simple scene basically build from starter content’s boxes. And here is my first problem. I’ve run through few tutorials but I hope I’ll find more and accurate answers here which helps me better to understand this engine.

First things first. Here are screens from my first attempt. Maybe I shouldn’t use so many elements and instead of it use one planar. But, if it is possible in this case to get rid of those strange shadows on the floor where two meshes are in contact? Also between walls and floor - there are shadows looking like poor Irradiance Map or something like this compared to Vray. Is it still related to the Light Map resolution per object?

Thanks in advance


Here is what I’ve done so far with extremely high settings for lightmass (I guess it took a hour to complete it in Production build settings - great to mention - thank for this tips, I;ve never changed it before and building in “preview” mode :frowning: ), I’ve also extend lightmap resolution for those cubes to 2048. I’ve also dig through web and find some quick tips from this video - . It is great that we can share ideas and everyone have sometinh to say, I;ve almost forgot how great forum works, thank you again guys!
I’ve also disable CastShadows in SkyLight. It allows me to get rid of strange shadows. But I’m not sure if it is correct now, I guest it is not because I should have “feel” of HDR around. So next step is to enable it and maybe add few lightmass portals to it? The next step is to use ActorMerge and compare results (as @DennG suggested ) . And after that I got plan to create few environments using Epic free packages, then do something myself from simple shapes. Lets keep finger crossed! :slight_smile: But before I;ll try to achieve best look in the best optimized way.

Here are images, this two interiors are both the same, just other angle, I can’t change order…

Hello again guys!

This time I’ve used technique which @DennG point - merging actors. This allowed me to get rid of strange shadows cuts.

Coming back to portals, I;ve create it for every hole which allows light to come in. I understand that they helps to gather photons and say “hey, there is where you should go mostly!”, am I right? Or is there much bigger idea behind this? Also, I have a question about open spaces, like cornes? Shoud I overlap both at the angle of 90*? Or just made it cubic and bigger? I’m rether familiar with offline renderers lightmass portals, they are working like lights. The volume of unreal’s are a bit new to me.

Anyway, here are images of my next experimenting, I;ve also attached few settiongs screens. Thanks again guys for your support and all help!

Last question, I’ve turned off abient occlusion in lightmass settings (world settings) but stay with the ambient occlusion in my PostProcessVolume. Is it generating realtime instead this baked if using World Settings? Or am I wrong?

Thank you and looking forward to your feedback!


Hello again guys,

Now I;m trying figure out how to achieve really soft shadow from directionalLight. I’ve use (Lightmass)/Light Source Angle and set it to 400. Results are attached. As you can see, the shadows are really poor quality. Is any way to use directional light to achive this moody look like screen from Bladerunner2 or I should use SpotLights with help of Point Lights to achieve desire look? I know that in real world it should be achieve by dispersion by fog/volume. Is Unreal working like this and can create soft atmospheric shadows like at foggy day?

Also, I’m using ExponentialHighFog. Now in this interior, while looking at the oposite side of the room I got strange Halo coming from the celling. Is it possible to have only light shafts but without this strange effect in dark areas? I’ve remember video about new fog system in unreal, need dig through it…

Thanks in advance!