Hi! I'm trying to use the principle shader to edit a piece of geometry so that it has mottled colouration. I've been following all of the instructions in this tutorial:

https://youtu.be/Fspeu7Q9c1Y [youtu.be]

I'm using the layer mix node, attached to two separate principle shaders (named differently, as are all of the nodes) and followed all of the exact steps in the video. When I attach the Ramp Parameter and Turbulent noise to the layer mix, suddenly the layer mix Alpha parameter goes blank so I can't edit it, and then the ramp colouration and any edits I try to make to the third piece of geometry stop working as if they are blocked. Also, there is a dotted line between the ramp and the alpha, rather than a solid line, so I'm not sure if that is the problem.

Does anyone know why this is happening or how to fix it? Thanks so much!

The disabling of parameters is normal when their associated inputs are connected. The value is now driven by the connection.

A dotted line appears for connections of different types to indicate that the type is being cast to the input's type. In this case the color ramp has too many components for the alpha input of the layermix so only the first component is used. It's more appropriate to use a float ramp, but it doesn't hurt to use a color ramp either.

I can't say why anything isn't working, try connecting the component that isn't working as expected directly to emission to see the value on screen.