I am working on an iOS applications using SceneKit. That means the main screen contains a simple 3d scene, with various small objects in it. The main interaction from the user is dragging and "throwing" these objects around.
The only button that is displayed by default is a plus button in the bottom of the screen. It opens a list for the user to pick new objects from. However there also must be an option to modify/delete objects already in the scene.
They way I was thinking about is using a long press gesture. Holding an objects for let's say 1 second would show a small panel in the bottom of the screen with options to modify color etc. The problem with this is that most of the interaction is already done through dragging, and a long press would often cancel the drag gesture before the user decides what to do.
Another option would be to have alternative interaction modes. If the user clicked on Delete button, clicking on objects would delete them as long as he doesn't turn it off. Same way opening color palette and choosing color, then clicking on objects would paint them.
I am very new to UI and UX design, so I would like any tips how you might solve this problem. My focus is to leave as much of the screen as possible for the 3d scene, and show UI elements only when necessary.