Hi all,
Did not come up with anything searching so maybe someone can help with a reply. 
Is there a keystroke, or other method, so that when using a circle mask you get a perfectly round circle? In Photoshop it’s the shift key… I’m not sure what the shift key is doing in the same circumstance in Zbrush - but not constraining the proportions.
Thank you
There is option when you click on stroke “Square”, activate this and you’re good.
Wow - talk about hiding in plain sight! I would never have found that! But that did the trick - thanks! 
LOL…I know, who would think to “square” a circle? It makes sense though since it works on more than just circles. But they couldn’t just call it constrain like everyone else? 