I dont get it. What i have to do to turn it ON?
Is there any “free to develop, pay to publish” option, like in Unity3D-Simplygon plig-in?
Simplygon is not offered with UE4. You will need to go to Simplygon’s website and sign up for their license to use it as a plug-in in UE4.
Is there news about this?
On the Simplygon site I see “Simplygon is directly integrated into the native editor of Unreal Engine 4”.
In the Unreal documentation I see “Automatic LOD generation uses Simplygon to create simplified versions of the base mesh to be used as LODs.”
Also: “Unreal Engine 4 leverages Simplygon to provide high-quality mesh reduction without having to leave the Unreal Editor. Developers can quickly simplify meshes, generate LODs, and immediately see the results in their maps.”
However, I am not able to find any specifics on how to set it up in UE4.
Simplygon is integrated into the engine but you must get a license to use Simplygon though.
You can find more information about this at Simplygon.com and by taking a look at this documentation link: https://docs.unrealengine.com/latest/INT/Engine/Content/Types/StaticMeshes/LOD/index.html
Thank you for your reply, but I have already read these pages. They do not provide information on what exactly to do… Maybe I am blind.
The Unreal documentation suggests that I contact Simplygon. Well, they are not easy to contact, since they don’t have that option on their website.
I Do Have a license for Simplygon. It is a free licence and I have already used the desktop application to simplify a few meshes.
How do I get to the interface related to Simplygon in Unreal Engine 4?
You’ll need the SDK and the source build of UE4 to do so. You’ll then need to recompile the engine once you’ve go this integrated. Here are the instructions and setup:
Overview
Simplygon ships with the Editor but licensees must first obtain a license from Donya Labs (http://simplygon.com/) to use this feature. Please contact them for further details on obtaining the license and SDK.
Compiling UE4 with the Simplygon SDK
Install the Simplygon SDK. The default installation path is C:\SimplygonSDKx64.
Create the directory UE4\Engine\Source\ThirdParty\NoRedist\Simplygon\Simplygon-X.X.XXXX\Inc\ where X.X.XXXX is the version you have installed.
Place the file SimplygonSDK.h in this directory. This header file is located in the Simplygon installation directory.
Edit Simplygon.Build.cs, modify the string SimplygonPath to match the above path.
Recompile the editor to gain access to the integration.
I won’t say “never,” but with the release of UE4 and it’s source availability this may be unlikely.
Thanks! Do you know whether there are plans to include this in a future version of UE4? (without having to build from source)
I checked out their prices, they are astronomical. I don’t know about your budget, but for most people they are out of our league.
As a rule of thumb: When a website does not offer to show prices in an easy way, they are usually extremely expensive and want to get you on the hook before they reveal their prices.
While Simplygon is not available for UE4, InstaLOD is! InstaLOD, an automatic LOD generation and mesh optimization solution is now available as a plugin for UE4 in early access. It ships with source code to allow you to use it with the launcher version of UE4 as well as your custom UE4 forks.
InstaLOD enables you to built LOD models directly in UE4 with full support for UE4’s HLOD capabilities introduced in 4.11. You can easily reduce your draw calls by merging multiple meshes into a single draw call by combining both polygon data and materials into a material atlas.
More information can be found on our website: http://www.instaLOD.io
And on our thread on the UE4 forums: https://forums.unrealengine.com/showthread.php?98648-PLUG-IN-Automatic-LOD-Generation-for-Static-Meshes
TL;DR: InstaLOD is an awesome automatic mesh reduction tool now available for UE4 www.instaLOD.io
Disclaimer: I am one of the developers of InstaLOD 
^^ that, its waaaaay deep breath WAAAAAAAY cheaper, and does a great thing. potentially easier to use for the less experienced ue4 user as well!