Training Livestream - Lighting Techniques and Guides 2: Dynamic Light - April 4 - Live from Epic HQ

WHAT

Rendering guru is back with more advice, tips and tricks for dynamic lighting. In a continuation of his previous lighting stream, will be going over dynamic light features specifically and will be taking your questions live. Beginner to advanced, you’re guaranteed to learn something new if you tune in!

WHEN
Tuesday, April 4th @ 2:00PM ET Countdown]

WHERE
Twitch
Facebook
Youtube

WHO

  • Training Content Creator - @TimHobsonUE4]()

Feel free to ask any questions on the topic in the thread below, and remember, while we try to give attention to all inquiries, it’s not always possible to answer’s questions as they come up. This is especially true for off-topic requests, as it’s rather likely that we don’t have the appropriate person around to answer. Thanks for understanding!

Project Files can be found here.

any info about dynamic GI future in the Engine would be great.

No plans to talk about that other than quick mention of LPV since that comes up occaisonally. The goal with these streams is to really discuss the features and settings that you already have to work with.

Sure, understand. As for LPV any advice for indoors would be great!

Thanks for this stream! Very interesting indeed…it would be nice to have tips on optimization for scenes where many dynamic lights are placed procedurally in runtime cast on movable objects. And maybe some love for VXGI, VXAO with some tips on those :slight_smile:

Got you covered on optimizations.

Not so much on NVVIDIA’s tech. I’ve used it a little bit, but not enough that I would be a good source of information. Goal here is to show out-of-the-box UE4 features more than anything else.

[QUESTION]
Would definitely love to see and understand the relations between cascading shadowmaps, cinematic shadows, far cascades and DF soft shadows.

Can you please touch upon ways to occlude skylight? For example - having bright outdoors and semlessly transitioning to a pitch-black indoor. Just turning down the skylight makes the outside darker too, as if the sun went out.

it’l be great if you talk about dynamic day/night cycle, and how to optimize it for better performance and quality! :slight_smile:

Looking forward for this! It would be amazing to talk (atleast a little) about DFGI/HFGI :slight_smile:

I would love some advice about this, too.

I suppose all I hope to see in this stream is getting the most realistic lighting you can get without lightmass.

Currently Dynamic GI is backlogged, I’m guessing that’s not going to change in the near future unless someone is working on it in-between projects. It’s been disappointing seeing various dynamic AO/GI features left in an unfinished/abandoned state. The Kite Demo for example is an unplayable slideshow when packaged with 4.15 compared to 4.8, so even going with what’s available in engine out of the box may not be as reliable as one would hope.

I’m now watching the redif of the first live training about lighting, Unreal has so much features for lighting and that’s pretty interesting.
I’m a newbie in lighting in unreal, I have more skills in unity, but I’m sure that I could get greater results in Unreal by practising, that’s why I’m looking forward for this live training.

I saw that it will be diffused on twitch, facebook and youtube, in which chat is it better to ask questions?

YouTube chat used to be disabled, but I think grabs questions off all 3 nowadays. When you’re unsure, try Twitch.

[QUESTION]
How should we build lighting for big open worlds with day-night cycle?

This was extensively covered in the past. A quick forum search should yield results.

In short: You don’t.

Here are some topics I’d love to be touched on:

  1. Best practices for how to use a dynamic ambient skylight to light open scenes that contain both indoor and outdoor sections - specifically when the indoor sections should be darkened.

  2. What kind of ambient lighting is ideal in dynamically lit scenes - especially indoor ones where all lights can be turned on and off? Outdoor dynamic skylights fake general GI/ambient lighting well enough, but are there any tricks with dynamic cubemaps or dynamic point lights that should be considered for getting decent looking ambient light in interior scenes?

  3. Best practices for distance field lights/soft shadows - both for point lights and for a directional sun. How often are these used in Epic’s projects and why? What considerations or limitations are typically taken into account?

Looking forward to the stream!

This is definitely a good question, especially since it comes up often for those just starting out with the editor or with lighting in general. I’ll touch on this during the end Q&A part of the stream with why this is.

In general though, I think a lot new people with lighting are told “Use baked static lighting, it’s best,” and then someone tries to use it on a large open world or even just a densely packed one and immediately run into hardware limitations (RAM mostly) for building the lighting or hitching issues where it’s trying to stream these lightmaps in/out. There are some good reasons to avoid static lighting for open worlds that would be good to repeat in this stream. :slight_smile:

Thanks for asking, I hadn’t really thought to cover that specifically since I was more focused on some of the features of dynamic lighting and optimization really.

I’ve got a few questions hopefully you can answer.

  1. How do you get the average color from a texture and convert it to an rgb color value for lighting effects? (I’ve been searching for an answer to this one for ages!)
  2. How do you get good sunny daytime lighting similar to gta v for example?
  3. Similarly what are good settings for night lighting?
  4. It’s possible to use three lights in rgb to project a color texture for stuff like stained glass but this isn’t great for performance so is it possible to use a single light or fake it somehow?
  5. Are there any interesting lighting effects you can show us that we might not know?
  6. What are some things to think about when using the forward renderer and vr?

Thanks.

That’s the point I want to make with these streams moreso than how to be a lighting artist. :slight_smile:

Few questions:

Does lightmap resolution on meshes affect dynamic lighting?

Suppose your scene is one static mesh and one light. The mesh is set to Moveable and the light is Static. What happens? Only dynamic shadows?

What about if the mesh is static but the light is moveable?

Also what is Stationary? The description says “Can be changed in game but not moved and uses cached lighting methods” Changed how? And what does cached lighting mean?

My game is a extremely large, low poly city. Theoretically, if I was using all dynamic lighting, could I shrink all my assets to get a better shadow draw distance with no loss?

What is happening here with the shadow in the middle and the transition between hard and soft? https://webmshare.com/play/vOmPa The box shadow outline transitions between hard and soft. Can I get it entirely soft or hard?