I am trying to remove most of the solder mask on my bottom layer so that I can mount a large heat sink on the PCB. I don't have any traces or any components. So what I did was I did a polygon pour on the entire layer and changed the layer to bottom solder and have it as a GND net.
However, for some reason Altium will not tent VIAs that are not GND that are in the polygon pour.
As you can see all VIAS don't have tents any more. So when I install my heatsink I will short.
I tried to do a solid region but that didn't work either. I even tried to play around with the keepout but had no luck.
What is also weird is that when I check the box to remove dead copper on the polygon I created for the solder mask, it removes all of the solder mask. It is like the solder mask is not connected to my GND. Which doesn't make sense to me.
I don't want to manually route the solder mask layer because this is a pretty big board and I am just showing a subset of it.
Any ideas? Thanks