Are circular menu / button interfaces intuitive?

Question

I have been seeing a few of these 'Circular menu' UI concepts around.

Recently a similar UI was proposed as a central element for a large project I know of. For example, one of the options would be 'Search' when clicked a search box would fly out, allowing you to enter your query. Other menu items would allow access to other key functions of the application.

Question:

Is this an intuitive menu interface? Do you have any evidence or research that can help determine the pros or cons?

Some examples:

Answer 1

These are generally calledRadial menus or Pie menus. Radial menus appear around a touch/click target and you move to the section of the circle to make your selection.

Radial menus are a design often used for tablets and touch. There's lots of research out there on radial menus:

• Modeling Hierarchical Menu Selections: Effects of Additive Factors
• The Hotbox: Efficient Access to a Large Number of Menu-items
• Supporting menu design with radial layouts

There's a lot of research in Human Computer Interaction on this topic: a quick search on Google Scholar for Radial Menu will find you many relevant papers. They're one of those fairly novel concepts that have some clear and supported benefits, but are a bit far outside the typical comfort zone to apply everywhere. I'll summarize some important, consistent findings:

Radial menus have these benefits:

• Short distance to target
• Equal distance to each target; no scrolling all the way to the bottom of a dropdown
• Many options visible at once; no/low Short Term Memory load
• Muscle memory over long term memory: after learning which options are where, all it takes is a quick swipe gesture to activate the control you want without looking in many cases. Windows turned this into the Flick Gesture system.
• Very natural action for touch/tablets, just slide your finger/stylus to the target
• Hierarchical radial menus can present a truly massive amount of options hidden in a visual hierarchy resulting in fast selection by experts.

They have these detriments:

• They're not common. Novel interfaces always have a learning curve
• All options are equidistant; sometimes you want to hide uncommon options. This can be done with multiple layers, but that gets complicated fast and harms the practical parts of radials.
• If using touch/a stylus to interact with them, your hand/pen will cover a small part of the menu. This effect is limited once you memorize the positions of the options

So for a rarely used app with a lot of buttons I wouldn't recommend them, but they can be great for power users, and they can be a simple pleasure if they're exceedingly simple (it's hard to get confused with a 4 button menu)

We've also had some other questions about radial menus with some good answers, though I disagree with the consensus here: Are radial contextual menus better than vertical list menus? I also answered this related question: Should I use a radial menu design for a touchscreen game?

It's important to remember radial menus are often designed for touch or stylus input, where they excel. OneNote 2013 has an excellent implimentation of this:

Answer 2

I believe this is a tangible control that has transitioned into the graphical domain, for better or worse.

It's easy to point out the benefits using this as a tangible control. The finger can rest in the middle and quickly reach each of the actions , without the user looking, by choosing a direction. Using it this way the interaction will produce a small risk of errors in comparison to interacting with a horizontal/vertical control with four options without looking.

In a GUI however I can't really see what the benefit would be, other than that it's an aesthetically pleasing contraption in comparison with its horizontal or vertical brethren.

Answer 3

I think these kind of interfaces are best suited for touch operated (or tangible) devices or as context menus. In both cases they offer the advantage of not having to move your finger or mouse pointer over a big distance while still getting access to the relevant option for the action you're performing.

The PC game The Movies offered something similar. When clicking on a character or a building, you were presented with a bubble menu. It contained the main actions and information about the character or building. Most actions opened another bubble with more specific sub-actions. As you can see on the screenshot below, this allows the main interface to be minimal so more of the game is visible while offering you an easy and intuitive way to access context sensitive actions without forcing you to click on a character, move your mouse all the way to the other side of the screen, click through 2 menu's and repeat the process for every item you want to interact with.

Answer 4

It involves less mouse movement (same as said that the distance between the actions is small). It is minimal, but if lots of presses of these actions are normal, it might be a reason to use these.

Also keep in mind that touch screens are getting more and more default, so this kind of control will be more comfortable.