UsingRenderTarget Does not work for Layer

[Evgeni_Popov]

You can do it this way:

GUI elements not visible on screenshot taken with Babylon.js Tools

It will work if you use CreateScreenshot instead of CreateScreenshotUsingRenderTarget. Else, the easiest way to do it is to use the camera.outputRenderTarget property to render the scene in a custom RTT. For eg: