Hello, from what I read viewport widget was disabled because it is not fully developed. I read somewhere that some changes in config or codes are need in order to enable that. It would be much easier if we would be able to enable this widget in experimental settings, thanks 
Enabling it will do you no good, the engine currently prevents multiple worlds from existing in a shipping game, non-editor build. The viewport requires multiple worlds. So if you want to use experimental widgets you’ve got to make more code changes anyway, hence, no checkbox.
I currently use a small hidden room where I capture with a SceneCapture and then mask the RenderTarget against a background color to show the objects on the UI, but that’s really not ideal, especially since I do this 10 times and 10 SceneCaptures with 10 RenderTargets already have quite some fixed overhead.
When will UE4 support multiple worlds? Why does it work in the editor? Shouldn’t it be possible to bring the functionality to a standalone version too? 
viewport widget is “secondary camera” in widget?
would be really cool to have that 
10 worlds would add even more overhead than your 10 components.
Pretty much everything can be accomplished with Scene Capture components, the multiple worlds just makes it nicer for them not to interact, but it doesn’t make anything faster. It would still be doing a separate deferred draw, resolve to RT and texture drawn to the screen in the viewport widget.
The editor supports multiple worlds, but I think only 1 game world, all other worlds are preview worlds. Why doesn’t the standalone engine support multiple worlds? No clue, kind of a framework team problem.
The viewport widget is a pocket universe, not a view onto the existing world.
Mmmm, pocket universes.
yep sounds cool
Thank you very much for explanation Nick, I can finally understand that decision.
By the time, I solved issue using SceneCapture component. I create component, render target texture, material instance in code then I set draw flags, so only skeletal meshes are enabled and then I add all other skeletal meshes in scene to hidden actors list. I exposed material instance to blueprint, so I can easily draw 3d portrait of any character. Alpha is also very simple, I use masked material and just connected multiplied (you need to use high number to prevent masking shadows on character) render target texture also to opacity mask.
