I’m not sure if I misclicked something, but whenever I use 3D-Viewer I cannot see the copper layer through the mask layer anymore. I’ve tried using Preferences > Reset to Default Settings, but this doesn’t work. I’m not getting any errors. Any clue what it might be?
Using KiCad 8.0.4, Windows 10 64-bit Edition
P.S. I wanted to attach an image showing a line on F.Cu which doesn’t show up on the 3D-viewer as an example, yet the forum doesn’t allow new users to upload images on Topics
It works just the same now as in the PCB editor. In the appearance manager on the right side there are little colored boxes, if you double click on any of them then you can set both the color and the opacity for that layer.
Welcome @Ricardo
See this Faq: new-member-information for information about posting on this forum 
In the Pref’s >PCB>Color panel, set the Mask’s Alpha (opacity as you want it… if it’s 100% color, you won’t see anything through it… Try a value of 50%…
Oops! That still applies for the PCB. You wanted for 3D-Viewer:
In Pref’s>3D-Viewer>Colors, Double-Click the Mask Color and set the Opacity…
Thank you, this solved the issue!
Setting the masking layer’s opacity down to 80 worked like a charm for me, highly appreciated
