Solder mask custom shape in altium

Question

I want to have a region in my PCB without solder mask while the other regions should have solder mask. I am not sure how do I do it in Altium? To be precise I want say a custom shape solder mask free region in my PCB. This i can use for tinning as I want more current conductivity. For such areas is it good to have many vias as I am drawing current from middle layers. Imagine I tinn it and air is trapped in vias. Will this have an adverse effect on my PCB ?

Also, should I first assemble all components and stuff and finally tinn the regions mentioned above or is it otherwise ?

Answer 1

With your PCBdoc open, go to

1. Place-->Solid Fill Region
2. Draw your custom shape
3. Double click on it to open up its properties
4. Set Kind: Copper, Layer: Top Solder (or Bottom Solder)

It might be easier to tin first, and then solder because then your components won't get in the way (you'll have hand/arm mobility). But if you can do it either way, then it doesn't matter, so no it won't have any adverse effects on your board.