How to plot a 3D matrix?

I have a matrix that cointains the value of ammount of light in the space. Since this value is almost everywhere zero except some point I'd like to draw the whole space transparent and see colors that indicates the intensity different from zero.

Answer 1

[Walter Roberson]

With recent versions, the volumeViewer() app can be useful.

[Luca Marchesi]

That's fantastic! Thank you for the suggestion :)