I think this tutorial falls down a bit because it assumes knowledge from the viewer that frankly may not be there.
In the video we see a click on the base colour and magically the model changes even though the base colour remains white.
I think the curvy help file needs to explain a bit about alpha channels.
Explanations i think need to be adapted for the lowest common denominator and that is usually me.
So alpha appears to be a mask type effect that can be stored in some image formats like tga (but not bmp ?). It can hide parts of the model but doesn't actually change the model. (So if we export the model the mesh is unchanged.)
Some paint programs will export what many users would see as the dotted selection areas as alpha channels and the selection area might have to be inverted to get the desired effect. (concept wise black becomes white)
curvy 1.5 you need to play around with the highlights to use alpha effectively .(highlights visible on alpha area)
sorry if this post sounds a little pedantic but so many applications can fail to get their deserved credit because there is a often a great technical gulf between developer and user.
For me curvy is such a great application that will do so many things easily.
It is a relief not to be playing with thousands of triangles (at least visually).
But new users are not led into it easily. They see these wonderful works in the gallery. (the elite ?) and the gulf between these and the introduction draw a few blobs is far to great.
What is missing is the in between practical use type of tutorial.
the "how do i do that" bit