Does it render in game but not in the viewport? If yes, this may fall under a known issue! 3D Widgets aren’t quite out of experimental yet. If this matches your case, I can look about for workarounds 
Hi,
I’ve already done one UMG 3D Widget withouth any issue by following the Epic official tutorial ([link][1]).
However, when I try to add another one, it will not even render in the viewport
I’ve tried to play around with the Draw Size values to see if that would be the problem but nothing continues to appear. I’ve also changed from that widget to the other one and it appears.
The original widget is like this:
Can anyone help me?
Oops I wanted to post this as a comment! I’m not sure how to fix this from my phone
No it doesn’t render in game. Only when the widget is drawn as 2D it appears.
When you remove all the other widgets, and make that the only widget in the blueprint does it render? if so then it would seem you can only have one 3D umg widget on a blueprint at a time would be my presumption, if not then your anchors are probably incorrect, if the anchors aren’t put in the right location, then elements become invisible, or more precisely what is being viewed is not the quadrant that the anchor is focusing on and hence is not in view.
hope that helps
Is this fixed in UE4.12?
Check sizes of image in X and Y (width height) and anchors