In that video the person makes a layer group and the makes a mask for it and modifies that mask constantly. I've read this thread but whenever I try that approach I can't modify it the mask the way the person in that video is modifying it.
Photoshop has roughly 4 different layer constructs:
- Pixel Layers - a layer consisting of only pixels (raster)
- Shape Layers - A layer consisting of a flood color fill layer in conjunction with a vector mask
- Vector Layers - a vector path which uses fill and stroke options
- Smart Objects - an embedded data file which can consist of any number of the above.
That video uses Shape Layers indicating Photoshop CS5 or older may be in use.
This is how Photoshop operated before Photoshop CS6. Since CS6, Photoshop has implemented Vector Layers which are similar in appearance but completely different than Shape layers in construct.
The difference is that with the newer vector layers there is no mask. You edit the actual shape on the layer as opposed to the mask. The appearance of the layers ultimately looks the same in the artwork, it is merely the construction of the layer which differs.
In the video, shape layers are being used. So, when the shape needs editing the vector mask is clicked and edited:
This is how things worked prior to Photoshop CS6 and vector layers.
With a vector layer you just click the layer and edit the shape directly:
The results are the same. The difference is how the layer constructs work.
With Photoshop CS6 or newer you do not need the separate vector mask. Just use the Pen Tool or Shape Tools to draw the shapes you want, then set the fill and stroke in the control bar:
So, in short, if you are using CS6 or newer, you do not need the mask. Just draw vector layers.
If you really want vector masks rather than vector layers you can set the vector tools (Pen tool and Shape tools) to create only a path:
Then, after the path is created choose
Layer > Vector Mask > Current Path and Photoshop will create a vector mask using the path. (This is how I created the vector mask in the images above). In general though, vector layers are just easier to work with and offer more features. Which is largely why they replaced the previous shape layers.