I\'m getting started with Unity to build Tango apps for Android. I have previous Unity and Android experience but I\'m new to Tango. I followed these guides: https://develop
Looking at your screenshot I would assume that your problem is the camera clear flag. There are 4 different clear flags that can be set on the camera in the Unity scene - these are Skybox, Solid Color, Depth only, and Don't Clear.
The behaviour you are seeing here is can be caused by both the Don't Clear flag or the **Depth Only* flag being set, which means that the camera's render buffer is not cleared with each frame rendered. In this mode, because the camera only renders objects in the scene and not the skybox, you are left seeing a history of past renders of the object without it clearing parts of the buffer where the object is no longer present.
The way to fix this would be to set the clear flag to Solid Color and set the background color to a value such as black. The chosen background color will be applied to the remaining screen after all elements have been rendered, clearing any previous renders of the object in case it has changed position relative to the camera since the last frame.
Similarly, using a Skybox clear flag will have a skybox texture visible where no elements are present.