How to show multiple states on a single button or knob

Question

The software I am designing has properties panel and some selectable objects. When selecting a single object, its a straight forward design since the knobs and buttons will show the value of the selected item. But what about when a multi select has been made?

The current version of the software shows the values of the first selected item, no matter how many items selection have been selected.

The image below shows 3 scenarios in the software, with the first, the second and last, both objects selected:

There is a standard on how to show check box states in this scenario - Adobe uses this (watch the "Align to pixel grid" property in the bottom right corner):

The yellow don't align, the red align, both selected shows a line as "multi state".

How can this design language be translated to a on/off button or a knob?

Answer 1

here's what I think

you are suggesting that there is a use case where the user wants to select multiple objects and for your mini dashboard to display a true value that represents the values of the selected objects.

some solutions

1)the user is looking for an average value of the objects and the dashboard should display that average. With the top knob that's easy, but will be meaningless for the button state.

2)the user is looking for all values of those objects and the dashboard should display all values

3)the user is not after an average value or all values but is performing a use case which is 'select objects'; observing the values of those objects is secondary. The dashboard should display an inactive state.

option 2 is probably out for display reasons. option 1 is of some use but will never inform about the on off state. Option 3 is best as is easiest to implement. You might need to figure out if the use case is valid though.

edits: "When selecting multiple objects, the goal with changing one controller is to set all the selected objects to the same value."

two scenarios: the dashboard defaults to one of the selected values eg the first, or averaged, and is editable. On edit, the new value is passed to all the objects. option 2: the dashboard defaults to a zero but editable state. In either case you need to reflect the change in state across all objects somehow.

Answer 2

Remove the indicator from the knob and print "Multiple Values" or similar text.

If the objects all have the same value for that property you can show the control the same way you normally would with the indicator and printing the value.

If they don't have the same value, most controls change to show the indeterminate state. For a knob, it seems like removing the indicator would be the way to go as long as it doesn't make the knob look disabled since you still want users to click on it.

In most tools that I have used, when selecting multiple objects, the controls allow you to assign a property value to all the objects at once. I would expect that setting a value using the knob would restore the indicator and apply that value to all selected objects.