How to see the solder mask layer in Altium PCB?

Question

Is there a way to see the solder mask layer (green coating layer) of a PCB in Altium? Is it a mechanical layer?

Answer 1

It's called "T-Solder" (top) and "B-Solder" (bottom) by default, and you can toggle visibility like any other layer. They're not mechanical layers, they're signal layer pairs, so when you flip a component to the opposite side the solder mask follows.

Here's the top solder mask for a TO-252 in single-layer mode:

And the same part with all layers displayed, but with T-Solder as selected layer.