[TUTORIALS] Photons Be Free: Mini-tutorials and other curiosities

[Tim Hobson]

Destructibles Overview and Q&A now available to stream on YouTube.

[Tim Hobson]

Twitch Stream: Occlusion Culling and General Lighting Review and Q&A

Forums post: https://forums.unrealengine.com/show...p-A-Tim-Hobson

Stream Subject: Occlusion Culling and Lighting

When: Saturday, October 10th

Time: 2:00 PM to 3:30 PM-ish (EST)

Outline:

YouTube Video: https://youtu.be/6MhsdwTW3SQ

Part 1:

• General overview of what is Occlusion Culling.
• Simple Examples of how the system works in UE4
• Methods to basic level design with Occlusion culling
• Methods to reduce pop-in of meshes
• Respond to Questions

Part 2:

This section will be more open forum. We'll go through the following Levels in Content Examples:
- Lighting
- Dynamic Scene Shadows

This part of the stream will focus more on general questions asked and see where we go. I'll setup some examples that come up often if time allows.

• Review Content Example Maps
• Answer Questions in each Section.
• Explore some simple examples not necessarily demonstrated in CE demos
• Quick look at Swarm Agent/Lightmass
• Explore a few of the settings for Lightmass in World Settings panel
• Answer questions along the way.

[tupikp]

Thanks so much Tim! Just found this awesome thread. What about lighting? Especially the Light Function system. I'm looking for how to 'faking' multiple lights from single light using light function but couldn't find any tutorial or example for that. Thank you again!

[Tim Hobson]

Thanks so much Tim! Just found this awesome thread. What about lighting? Especially the Light Function system. I'm looking for how to 'faking' multiple lights from single light using light function but couldn't find any tutorial or example for that. Thank you again!

Lighting is definitely something I would like to dedicate more time to do for any tutorials or discussions, but I've not had the time as of late to really get anything out there.

As far as Light Functions go, this is just a gray-scale material that is applied to your light. Not exactly sure what the usage would be to make it appear as multiple lights. If you could clarify with an example or some more in-depth explanation I can possibly help.

[catalejo]

I think this is relevant to this thread

http://www.scriptspot.com/3ds-max/sc...o-skinned-mesh

[tupikp]

Lighting is definitely something I would like to dedicate more time to do for any tutorials or discussions, but I've not had the time as of late to really get anything out there.

As far as Light Functions go, this is just a gray-scale material that is applied to your light. Not exactly sure what the usage would be to make it appear as multiple lights. If you could clarify with an example or some more in-depth explanation I can possibly help.

A very good example of that would be car headlights. So instead of placing two spotlights, maybe it's possible to just use one spotlight with the light function, and it appears as if we are using two spotlights.

[TheFoolsGuild]

Hi Tim,

I'm running into a bit of a bottleneck issue. I was hitting the cap of 2000, and so tried to introduce further depth levels to my destructable mesh.
Initially, I used a fracture map to fracture a wall in to large chunks which outline some of the stones in my stone pattern. I end up with say 20 islands. I then have to add those to a fracture group to enable me to voronoi fracture those islands into smaller groups. My plan is that when extended structures are enabled and a dm takes damage, it will limit the number of awake chunks. The problem is, if I try to import any physx object which has used fracture groups, the editor crashes.

Is there anything I can do about this?

[Tim Hobson]

The problem is, if I try to import any physx object which has used fracture groups, the editor crashes.

Is there anything I can do about this?

If you're getting a crash it's best to make a post on the AnswerHub. You can see more information in my signature for this.

I'm not aware of any fracture group issues, but then again, I've not really used it so I can't say for certain. Make the AH post with steps to reproduce, include your call stack along with the Machine ID and Epic ID and I'll assign myself once it's in.

My plan is that when extended structures are enabled and a dm takes damage, it will limit the number of awake chunks

Whether the chunk is awake or sleeping it will still be a bottleneck for performance, thus why there is the limit of 2000 chunks per scene. When the fracture mesh is loaded it will load all the chunks and collision bodies, whether the chunk has broken free or not. You can use PXVIS Collision console command to view these collision hulls.

[Joure]

Hi Tim. Thank you so much for the indepth tutorials and tidbits of information. It's so much user friendly then the standard documentation you have no idea how much this is appreciated. Thank you, really....

[TheFoolsGuild]

Many Thanks for the quick reply, Tim. Typically, it seemed to be a physx version issue. We updated the latest binaries, and I seem to be able to get everything importing now.

Thanks also for the insight on the bottleneck. So, if a dm has a 0-solid, 1-islands, 2-brick chunks, and I damage that, and in doing so the damage radius causes neighbouring dms to wake, each one of those will wake as a depth 2, effectively?

Also, have you had much luck with fracture maps? I've managed to get my level 1 chunks to break nicely, but afaik there's no way to run a separate fracture for deeper levels.

Best wishes ( and great tutorials vids, btw),

Jack.

[Tim Hobson]

So, if a dm has a 0-solid, 1-islands, 2-brick chunks, and I damage that, and in doing so the damage radius causes neighbouring dms to wake, each one of those will wake as a depth 2, effectively?

Yes, If the DM any of the levels has received enough damage to fracture any part of that depth it will go ahead and break the chunk off and even though the others appear to be a single solid piece they will already switch to that depth.

So your example is spot on. Think about it as just switching out the mesh to another one when enough damage has been received. On the Trello board for the UE4 Road map there is a Wishlist/Backlog item for dynamic fracturing that may allow something like this. Hopefully one day that can be worked on and added.

Also, have you had much luck with fracture maps? I've managed to get my level 1 chunks to break nicely, but afaik there's no way to run a separate fracture for deeper levels.

I've not really used them, but I did a quick test in PhysXLabs and I'm able to use a Fracture Map with the base mesh and get Depth 1. Then it will dump back to Slice mode. I'm not sure you can use more than one fracture map or use the voronoi method on any of the fracture groups for other depths. This is my initial reaction while doing simple tests. There could be something else there that I'm missing, but I'm not 100% sure since I've not used this part of PXL extensively.

[Tim Hobson]

Occlusion Culling Overview now available to stream on YouTube.

Someone had requested this from my old Twitch stream that was expired.

[Tim Hobson]

Lighting Sample: Simple Backlighting

PROJECT DOWNLOAD LINK


This is two simple examples of Backlighting for a Logo Mesh against a wall. This method can be used for different types of meshes.

Method 1: This uses a Static mesh that has no backface with static lights recessed inside the mesh. The lights use a low radius and low light intensity. Because the lights are static there isn't any real overhead for using so many to get a nice backlit glow around the mesh against the wall.




Method 2: This uses Emissive Static lighting to generate static lighting from the emissive color of the material. For this one, I used the same mesh as before, except it was capped on the back to close the mesh. I used two materials on this asset. The base color on the front for the text, and the back is using the emissive color that is multiplied by a scalar value. This scalar value determines how bright the emissive color will be and ultimately how bright it will be when you build lighting.

In order to use Emissive static lighting you will need to select the mesh in your scene, then in the Details panel you can enable the option "Use Emissive for Static Lighting." Then when you rebuild the lighting you should see the results. If you notice any artifacts or blockiness with the emissive static lighting you will need to increase the Lightmap Resolution of the mesh the light is being cast onto, in this project, the back walls lightmap resolution was raised.




There's really nothing special about this project, but since it was created for another user and is probably something someone else may like to use or test in their own project, it's here for all interested parties.

[Kajisan]

Hello Tim.

i ran into a small problem using DM's in our maps: Once i destroyed all chunks - and nothing visible is left,
the DM is still active in the World Outliner and got some random left-over collisions.

It prevents a player from digging a tunnel and just flying through because the invisible DM collisions stops it.
Any idea how to destroy the actor, once all chunks are gone?


Best,
Tobias

[Tim Hobson]

Hey Tobias,

I saw your post on the AnswerHub here: https://answers.unrealengine.com/que...leftovers.html

I've assigned myself to look into, hopefully, at some point this week.

Tim