[SUGGESTIONS NEEDED] WIKI Troubleshooting Guides

Hey Everyone -

For those who are unaware Tim Hobson and myself worked hard to get a common problems troubleshooting guide out for lighting, A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums, and it has gone over really well. It is by no means a comprehensive guide as it doesn’t deal with more advanced lighting setups, but it offers some answers to very common lighting issues and that’s what we were really shooting for a common sense guide for the basic lighting problems.

With the success of this troubleshooting guide, we are looking at adding two additional guides, one for materials and one for post processes. These two topics though are quite extensive (not that lighting isn’t), so I thought I would ask you guys and gals here what are the most commonly asked questions from beginners or items and concepts you are constantly looking up. Keep in mind that we are looking for common items or ideas not necessarily how do I make this particular item.

At the same time, feel free to suggest some items for the Lighting Guide as well.

We will be monitoring and conversing with everyone here, so feel free to start throwing those suggestions our way.

Two days and no suggestions makes Eric a sad panda.


Here are some suggestions to get us started. A rough unpolished list of topics/ideas to cover. :slight_smile:

Post Process:

  • Why does my scene get brighter? Turning off Eye Adaptation (Auto-Exposure)](Auto Exposure (Eye Adaptation) | Unreal Engine Documentation)
  • Using Post Process to give some control over lighting in a level.
  • How to add or remove more JJ Abrams (Lens Flare) in your scene?](Lens Flare | Unreal Engine Documentation)- Why is there no post process effects in my scene? Engine Scalability
  • How to make the post process affect the entire scene without scaling the volume? Unbound check box
  • Some examples or situations with Blendables for post process. Enabling and disabling them for effect.
  • Overview of Bloom Settings for better control of your Bloom output
  • Controlling Light Propagation volumes (Link back to Wiki Lighting Guide for some information there as well)
  • Anti-aliasing tips and issues
  • Animorphic Lens Flare (not possible…yet with PP) particle example to demonstrate
  • Screen Space Reflections tips
  • Modifying Post Process via Blueprints
  • in UDK I used post processing mixed with Scene depth priority to achieve certain fx. since SDPG is gone now, what other strategies can be used to tackle draw order?
  • how to properly use multiple postprocess materials as blendables. Is there a way to give them different weights or something like that?


Cool post process setups:


  • What does Specular do in a PBR Material?
  • which textures can be used in a material/are required?
  • what shall I do with an albedo, glossy,… texture?
  • whats the difference between a shader and a material?
  • why is my material stretched when I apply it to my mesh?
  • Why is my texture so big/small on my mesh? texture coordinate node)
  • World-based UV applications? i.e. tiling /blend based on distance? (ie. Landscape blend distances, etc)
  • Forward vs Deferred examples: UDK vs UE4. What’s the deal?!

Sticky this thread so that it stays at the top -> more views and replies :stuck_out_tongue:

To make Eric happy :wink: ->

bold = questions which I have to answer pretty often
-which textures can be used in a material/are required?
-what shall I do with an albedo, glossy,… texture?
**-whats the difference between a shader and a material?
-why is my material streched when I apply it to my mesh? **

More will follow from time to time

I typically try not to Sticky threads unless there is a real need. I’ll do it for now until we get started on this one though. :wink:

Thank you for the suggestions. This is exactly what we’re looking for! Those questions that get asked often that are typically the most common ones. They can be simple to complex. We’ll par down and organize this as we see fit at that point, but it’s always good to have a long list to work from than scrounging to come up with basic topics.

Thanks, Fighter! I’ve added your suggestions at the top.

Hey Eric hey Tim,

you Guys did an already amazing Job on the Technical side of the Lighting.

I like to suggest a small scale Example Project that Covers some common Scenarios we See in Games. Not only providing the Example “as is” but also Guide the Readers through the Decision Process (in a not so technical way) why the Lightning is Setup in a certain way and the Settings you made.

I imagine something like a little Outdoor Forest Area with a Deep enough Mine where the Outdoor (sky/sun) Light cannot reach it. And a small Pub/Inn nearby. So we get some different Scenarios on this little Map:

  • Outdoor
  • Indoor with Outdoor Light
  • Underground
  • Optional: Underground Cave with Glowing stuff like Mushroom/Crystal

Just some Questions to get you guys started:

  • How we approach this on a Static Level without a Dynamic Day/Night Cycle.
  • How we transition between Outdoor and Underground, do we need to Change some Light Settings as we Enter the Mine to make it Work.
  • What if we have a Dynamic Day/Night Cycle what can be safely baked?

You Guys can also use this Example Map to add Guides to upcoming Features like Ray-Traced Distance Field Soft Shadow and whatever comes along in the Future.

The Important thing is to really Guide the Readers through the Scene because its really difficult to understand the overall Composition of a finished Scene without digging into it for many hours to figure out the decision making Process that leads to the Result we See at the end. I think many Readers will have less Problems to Setup Lighting afterwards.

Some of this goes a little outside the scope of what we have planned to do unfortunately. Eric and I are the only ones working on this so it cannot be anything overly complex with lighting for the lighting guide. Our main focus is to have simple examples of progression (ie. showing the difference between using ambient occlusion vs not). These work best, in my opinion, for those new to UE4.

Eric and I have discussed some options for side projects that would incorporate some of these things as well. We do like to do side projects and expand our efforts with the editor through practice in this sense. We have not fully nailed down what we will do, but we do have some ideas in the works.

One such idea we’re contemplating at the moment is a hospital. We would have hallways, lobby, reception desk, windows, exterior courtyard type area. We feel that an environment setup like this provides enough that we can show statically lit transition from exterior to interior n the hallways with the windows along with sections that are not lit by exterior direction lighting. Again, time constraints have prohibited us from being able to work on this outside of work (mostly on my end since I’d have to start getting the assets prepped and modeled). These are projects that are not created by Epic or requested by Epic for us to do. We do these when we have the time and feel like working together on something we both enjoy. (although Eric will slap my hand on this project if I start creating material instances of instances of instances again. :slight_smile: )

This project would be an exploration of using Statically lit objects, materials, and post process.

So to touch on some of the things you suggested and how they would work in a simpler scene like we have as well:

-Transition from outdoor to indoor would be taken care of with the hallways and windowed courtyard area.

  • for the Underground, our idea was to have some sections of hallway that have the lights turned off. So that would be a similar choice there.
  • Glowing stuff: The idea behind the reception desk would be an exploration with materials using layered masks, flipbook animations for the computer monitor, Emissive glow for static lighting on some things.

Unfortunately, we still want to keep anything on the wiki guides more in the simple area of demonstration with a clear “this does this when not enabled” and “it does this when enabled” type area.

As far as Distance Fields example project I think the Kite Demo that Epic did is a really great example. If I did a sample project of my own with them it would be a while as some of the Distance Field stuff is still being experimented with and developed.

Day Night cycle statically lit parts is not too complex. I can add that to our list on the lighting guide.

Thanks for the suggestions and hopefully over the next couple of months we’ll get some awesome stuff together for you all! :slight_smile:

Some issues i’ve been struggling with:
-Lighting : Cove lighting (recessed indirect) or linear lighting (even lighting along a path) - i realize this may be more technique rather than FAQ though
-Materials : World-based UV applications? i.e. tiling /blend based on distance? I still don’t fully understand the landscape material in the landscape marketplace example, so maybe it’s just me
-Post Process: in UDK I used post processing mixed with Scene depth priority to achieve certain fx. since SDPG is gone now, what other strategies can be used to tackle draw order? (this is sorta a material issue too i guess)

hopefully this stuff isn’t out of scope, and thanks for the already awesome guides!

Hi Paradoc,

Thanks for the suggestions!

Lighting - There are plans to add some examples with indirect lighting issues that come up often (Modular Asset Lighting Problem - Content Creation - Unreal Engine Forums). I’m about half-way through my work with that one. Between that and lightmass crashing or not building lights issues, these are the next big ones to get up on the Wiki. They just take more time.

Materials: I’ve added this. Eric is our materials and VFX guy so he can setup some simple examples to break down what’s going on.

Post Process: I’ll add this as well. A lot of the lighting, materials, and post process stuff can go hand in hand.

It may be helpful to include a image of the effect in UDK as well so that Eric has something to work from as a target when trying to recreate. He’ll probably have more to say on the materials and post process stuff than me though as that is more his forte.

One thing I’d be curious about is how to properly use multiple postprocess materials as blendables. Is there a way to give them different weights or something like that?

Might not be a FAQ per se though.

I’ve added this to the list as well. Thank you!

If it doesn’t fit into what Eric feels needs to be covered we’ll nix it. Maybe when he gets back and has a chance to look he can possibly offer some tips here as well if it doesn’t seem like something that should be in the Wiki guide. I don’t have much to offer though since I don’t use more than a single pp material really.

I really hope you guys find time for that Hospital Project it sounds really good to me.

From my Point of view its easy to understand the technical Stuff but a lot Harder to make a Composition of Lights to get good looking results.

**@Eric Ketchum
@Tim Hobson
To tie in a related thread which touched on lighting & rendering in different engines :-

Could you PUNCTUATE the points made in the links with regard to UE4’s capabilities today, in the near future, and in the distant future?

Contrast UE4 with UDK too to drive home the point. There’s so much info overload on the forums its easy to miss this gem in the making. Thanks so much!

Yup, I’m very familiar with that particular thread, but I won’t be touching on anything in regards to DFGI until it’s available in the editor without editing the ini files. It’s still in an experimental state where thing are certain to improve or change drastically. Daniel makes posts in there often with updates and answering questions.

This also goes extremely beyond the scope of what these Wiki’s are supposed to represent. These are simple troubleshooting guides to help with the more common questions that come up. Eric and I appreciate any input in that regard but this up the alley of one of our rendering engineers to discuss. That particular thread is probably the best place for that type of discussion as well.

I also can’t really comment on other engines as I’ve only ever opened Unity a couple of times back with version 3. With CryEngine I’ve only ever opened their sample scene. I’ve seen the demos and images of what these engines are capable of, but I have no more knowledge than that about their lighting capabilities.

I’m not part of the rendering team so I can’t speak for them on where the engine will be in the future and even the distance future, Although I’m hoping for a holodeck powered by Unreal Technology at some point! :wink:

The one point that would fit well within the scope of what we would like to discuss in these is lighting and materials with forward rendering vs deferred. Some things cannot be done because of this so I’m sure Eric will have some good examples to use in the materials section.

Another postprocessing guide that would benefit a lot is how to “properly” set the values for Depth of Field effects.
I remember having quite a lot of trouble trying to dial in the values for my shot.
Maybe on this same subject, explaining how to do this dynamically/procedurally or how to animate this would come in handy to a lot of new users