LoD terrain

One of the guys on the team is looking at using World Composition and wanted to LoD the terrain. While i have started to get in contact with Simplygon, Im looking at other options just in case its not viable.

what are other options for terrain LoD besides Simplygon?

When you use the landscape tool -> it already has a pretty good lod system and you can change the LOD distance in the details panel :slight_smile:

Yep! What said. Basically in the Levels window, you can highlight all of your levels, then click the Details option. The bottom half of the details panel has options for generating LODs of your Landscape Actors. You can customize how/when they’re loaded in and out, and to what level of detail they are. This is free and built into UE4, no Simplygon required. However, this does NOT generate LODs for the actors/meshes within each of your landscape tiles (trees, bushes, etc). That’s where simplygon would come in handy I believe, but it’s fairly easy to create your own LOD’s for your own assets! Good luck.

Also, if I’m not mistaken, this feature is only available in 4.8 +.

thanks much!

That is just fine, but why does it say, that Simplygon is required, in the info popup?

I’m afraid that feature required Simpolygon installed otherwise when you navigate to that window, there’s not option for generating LODs for landscape chunks.

@Chieling, your teammate is absolutely right about getting Sympolygon. The only way around it would be to create LODs manually for each chunk of the landscape and then program them to when appear/disappear. And that usually doesn’t end up being as good as what Sympolygon might do. (I have not tried it).

Some terrains are just so big like 60 tiles. It’d be a waste of time and resources to do the LODs manually.

here the pop up. Version 4.8.2

@GAME3D, I am on 4.8 and those “Generate” buttons aren’t there. When you do click on the Generate is it working properly? Can you check out with wireframe view to see if it’s working?

i can make different LODs. and settings, and it seems to work well. Just to be sure, did you setup how many LOD you want in num LOD? And also the level must be active.

What i wondering, doe’s it need a Simplygon license to use that feature? At least, it seems to work in UE4.8.2 without installing any thing.

Simplygon is only required for static mesh LOD generation, but prior to 4.8.2 even LOD generation was stuck behind that same wall, not because it requires it, but thats just how it was setup, in 4.7 and 4.8, you can change the source and allow it to build Landscape LOD without Simplygon, and looks like in 4.8.2 they finally uncoupled it.

As far as I know that generate LOD was supposed to create much lower poly LODs for landscape than the currently dynamic landscape LOD. But I’m not seeing anything.

Last I remembered, from 4.7, it was configurable, based on a percentage, at really low amounts, it would be considerablly lower poly than the main landscape, but you would also loose just about every detail, and at the higher end it would match closer to the lower LOD levels of dynamic terrain.

I’m just testing right now with 1-10 percent, which means it should be very blocky but it’s not affecting it.
If you had time, I would appreciate it if you look into it on your end and let us know if it’s working there.

From 4.8 generate sub-level LOD requires Simplygon only for merging static meshes. So when Simplygon is not installed - all actors (except landscapes) will be ignored and removed from generated sub-level. Details percentage works only for static meshes, we have renamed it to ‘Static Mesh Details Percentage’ in 4.9 to reduce confusion. Landscape has his own settings for simplification ‘Landscape Export LOD’. By default it exports same landscape LOD which is specified in landscape actor details ’ LOD Level’. But you can override it to another specific LOD number. Landscapes have LODs from 0 to 7.

Hello ddvlost,

As much as I’m trying, the only thing I see is the default dynamic landscape LOD. It never streams to a simplified LOD neither when in editor nor when simulating or playing.
But maybe that’s just me.

Make sure you have setup streaming distances. Sub-levels streaming distance is set in layers (top bar in world composition minimap window). By default all sub-levels assigned to ‘Uncategorized’ layer, which has streaming distance = 50000 units, which is 500 meters. When your camera is further than that distance sub-level will be replaced with simplified version, if it has one.
You can create your own layers with your own streaming distance and assign sub-levels to it. Just add a new layer by clicking ‘+’ button, load sub-levels -> right click on them -> assign to layer -> save.
Simplified sub-levels also have their streaming distances, which can be specified in LOD details panel, when camera is further than that distance simplified sub-level will be unloaded.

Thank you for the time you put for the explanation, everything is working as expected except the tiles only get unloaded and not replaced with a simplified LOD. For example distance for the tile to unload 10 meters, distance for the LOD to appear 10 meters. So as soon as the tile is unloaded then LOD should appear but it’s not happening no matter any distance I experiment with.

Hello, I am currently working on world composition. How did you get past this problem if you did?

So any meshes we might need in the LODs we have to LOD & place manually?