Lukas Stratmann

UE4 Light-baking on a Laptop - Part 2

Work In Progress / 29 April 2020

Lighting is such an important part of your scenes - one might say the most important part. I am really happy to work with amazing lighting artists who make my Level Art look good - but at the same time as I can vocally express my intentions, I always felt like my actual lighting skill sucked or at least is sup-par.

Time to get better at it.

I spent my last couple lunch breaks looking into the tech behind real-life lights and watched a rather reassuring interview with Boon Cotter who mentions his gut-feeling and lots of iteration to get amazing results (seriously his Uncharted 4 work is awesome).
And I think the last part of that is important. Iteration. No need to rush something if you can slowly dial in lighting and get a feeling for the atmosphere and how to get it.
I did switch Unreal over to manual exposure and tried my lamps by their real-life values. Oddly enough this scene renders out like this with a Shutter-Speed of 60 and an ISO of 100. If my (limited) DSLR work is anything to go by I would have expected an ISO upwards of 800 and a much, much, slower shutter. Either UE4 is off - or I am doing something wrong. That aside iteration and changes to the light intensity and temperature have brought the light closer to what I set out to have.

Even if it's slow on a laptop I love the result of baked light. There is an amount of atmosphere to it you just don't yet (or ever) get from dynamic lights. The way a good light bake spills into a room and almost looks like a still render -- you can almost feel it.
I think I'll leave the light settings like this for now; it's time to move on and come back later.

Because baking light takes a lot of down-time I have some time to spare during lunch to push some other ideas.
This is a high-poly model for the lamp in the scene on the left (blockout in the screenshot above):

high-poly with solid color materials - ready to texture.

I have had this idea for a while now: model and texture a high-poly.

Do all that texturing procedurally (and in Blender). Then bake it down to a low-poly. In theory, what this means is a photorealistic high-poly and textures are baked into a low-poly game asset. Think of it as photo-scanning - except its partly procedural, digital, and never leaves your computer.

"Digital Photogrammetry" so to say. (Because who wants to go outside during a pandemic anyway.)

I have a high-poly lamp now. Time to spent a couple of days on procedural texturing - I'd like to not use any image textures; avoid repeating details. Again, in theory, this means no matter the low-poly polycount or texture size you can come back in 10 years and bake out a higher resolution version - you basically have a near-infinite detailed version always at the ready to bake down from.

I'll see how it goes and will write about it - if it goes well expect a Blender Tutorial for this workflow.

-Lukas

UE4 Light-baking on a Laptop - Part 1

Work In Progress / 27 April 2020

This could be considered the second half of might "Light-Exploration"; the flip side of the Unreal Engine 4 lighting coin. I did a lot of work with Unreal Engine 3 and am well familiar with lightmass. We are also using baked lighting in my project Sails of War.

So mainly focusing on the actual lighting skill over learning how to use lightness.

So set and done then? Put down some lights, do what you do best, bake, publish, profit! ... Not... so ... fast.
"Fast" is a good keyword: I am on a (decent) 4-year-old gaming Laptop and light baking on what can only be described as a below-average CPU is a ... pain. One of the reasons I was exploring fully dynamic light in my last post is exactly that: not wanting to wait hours upon hours to see small changes take effect. That aside baked light has changed from UE3 to UE4.

This scene has a Skydome with an HDRI texture and a skylight capturing it to project its light. Works well and respects the fog, atmosphere, and HDRI rotation. A Directional Light is used for the sun and harder shadows casting light in - one smaller light for highlights. Reflection Captures do their part to get nice and realistic looking reflections. - Though it still leaves the metal chairs in darkness which does not look great.

One question you might ask is: why use baked light in the first place.
We are in the age of all dynamic all real-time - that much I would agree with. But... there still is no great way to get full Global Illumination in UE4 - unless you bake it. And with a scene like this; with a scene that has windows to the outside, you simply NEED baked light unless you are willing to forgo what will make it look good. (Maybe I should work on an outdoor scene next where you can get away without real GI.)

I am not sure if I will keep on working on this. Having to bake is a royal pain and this is only Preview light - takes about 10 minutes. I don't even want to know what Production would do. -- I do want to get better at lighting but wanting GI in UE4 means having to bake.

If you have any input on the light or scene feel free to share.
Until next time,
-Lukas

P.S.: Thanks to Abel Dopazo for his input over the weekend.