Training Stream - Hierarchical Level of Detail - Nov 15th - Live From Epic HQ


Ian, Alexander, and Tim Hobson will be taking a look at the Hierarchical Level of Detail system in Unreal Engine 4. We’ll dive into what it is, how to enable it, and how and why to use it.

Tuesday, November 15 @ 2:00PM ET Countdown]


Alexander Paschall - Community Manager - @UnrealAlexander](
Ian Shadden - Senior Technical Writer - @Shaddenfreude](
Tim Hobson - Engine Support Technician - @TimHobsonUE4](


This picture raises so many questions.


One question: How is collision handled for the HLOD mesh. ?
(As the documentation is not mention it explicitly…)

Tim already gave some pointers, but a detailed show-and-tell would be nice :slight_smile:

Looking forward to the stream :slight_smile:

Awesome. Looking forward to this. Thanks for all the hard work that goes into these streams.

Im having many issues with HLOD… This system never really got off the ground for me… always been broken in 1 way or the other… it crashes unreal editor quite often when generating proxy meshes for certain areas. I noticed one reason for a crash in 1 area that fixed it was literally being forced to disable blueprint meshes from being included in it, but other areas are simply static meshes with nothing fancy in there… and it crashes the editor. I dont generate new textures… it should simply be a merge of meshes.

Cant wait to learn how the Hlodsystem works. Thanks in advance!

I totally want to see this, but will this only be live? Or will it be available to watch after it’s over?

It’ll be up very soon on the Unreal Engine YouTube channel so you can check it out. :slight_smile:

Awesome. Thank you, Tim Hobson!

Archive is now up, enjoy!

Thanks for the video, It was very interesting, very useful future!
Now I have a question, would be possible to do the inverted engineering option for cinematics ? Here is what I mean, If this tool was made to bake actor and make it easier later for the machine run, giving the game a speed boost, could you make the opposite to bake one single high resolution object or group of object so it does not pop when rendering cinematic on sequencer?
See the example below(rock):

Lets say that I select the rock element on the video and make it a baked version of it, so when my camera is moving it does not change the LODs.(I changed the distance of LODs on the rock but the engine still stream it as lower resolution when the camera moves away.)

Even were to go for Dinner and came back later, would be great to see just one Rock streaming on the render.

I’m taking a few month off from vfx to research about real time rendering for cinematics and the biggest issue of it is this streaming popping when the camera moves forward or backward.

I was checking the best UE4 cinematics and they avoid this kind of movements, you can even see it on the kite demo when the camera move forward with the kite at the middle of the video.
Time 1:02 - 1:13

The kite demo was made with the best resources at the time I would guess, and we can still see a bit of the popping, for someone that is just staring on unreal like me it seem a hard problem to fix.

Any thoughts about it?

By the way UE4 and your team are super awesome! It is fun watching you guys talking! 8)


Someone on the Stream asked about HLOD LOD colorization not working. I checked this in 4.14 when using the Viewmode > Level of Detail Colorization > HLOD Colorization

This setup has two HLOD levels.


  • Green - Base meshes with HLOD proxy used.
  • Blue - HLOD Level 0
  • Yellow - HLOD Level 1
  • Addtional colors for additional LODs. These colors can be checked and set in the BaseEngine.ini file. Look for “HLODColoration=”


If you’re rendering out a cinematic for the images you could just use r.ForceLOD and use a value from 0 to X for the LOD you want to force. By default it’s set to -1 which turns it off so that LODs work properly. Using a value of 0 will make all meshes uses Base LOD0 at all times.

From the Kite Demo video the biggest thing you notice there popping in is the shadow on the rock. Not the transition of the mesh. The rock has a noticable pop in shadow for one of them, This is the distance for Cascaded Shadow Maps that was set for the dynamic light being about 1600 units. The pick flowery grass was a transition with the foliage fading in. The Kite Demo only uses grass foliage around the player camera so as you move through the world it’ll fade in and out as you move to stay near the player only and maintain performance. This isn’t really an HLOD issue and falls more in line with Cinematic Rendering which would be good to post under the Rendering section of the Forums for a more involve conversation about techniques.

Thanks Tim for the replay. :slight_smile:
I will check the Render Section on the Forum, and Yes I did force the LOD to 0, and I just found out on the weekend that if I turn off the collision, the pop on the video I post was gone!
Also I checked UE 4.14 and I saw the new options on the LOD section, they are awesome! Now we can remove the lods as well.

Thanks again!