Nothing happens if I want to make them real.
And it's not possible to render them.
In the screenshot you can see, that the twigs are in the viewport but not in the render (right). In 2.79 it's working fine.
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Short description of error
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).