I recently went back to basics for a weekend and cracked open the old GTKRadiant editor, just to see what made blocking out levels in that editor so much fun back in the day.. I would like to report that ProBuilder is obviously way more sophisticated than the basic BSP brushing abilities in GTKRadiant, however GTK does still have a few nice features I would love to see ProBuilder possibly adopt. Here was the four main competitive features I personally found worth investigating to see if might help expedite the end users experience in using ProBuilder/ProGrids. Hollow out feature. In GTKRadiant, you can simply draw a block out (probuilder cube in unity) and goto selection -> make hollow. The end result is that each side of the block is replaced by cubes. Comes with two options for either overlapping or touching, that defines how the cubes meet together. The users current grid size should define the thickness of the hollow FYI. This feature would save us end users a ton of time. Being able to resize blocks without needing a transform gizmo or having to specify selected faces or verts. In GTKRadiant, simply have a box selected and then click / drag just out side of any side from a X, Y or Z viewport and box resizes. ProBuilder you have to select faces or verts to do the same job. This would not replace face/vert moving, as these would supersede any quick resize ability once you have a vert or face selected. Grid size hot keys. I know we have the - and + in ProGrids.. however the ergonomics of grid control in GTKRadiant feels way faster by simply having the number keys (1 - 5) be mapped to grid size. GTKRadiant has far less grid sizes than ProBuilder, so it might just be a matter of mapping the - and + to just 1 and 2 keys. That said, I realize I can change this myself in preferences, but please consider this possibly as maybe default keys in later release? Vert selection mode down to single hot key of V. I found switching in and out of vert mode in GTKRadiant to be way quicker due to it being a single key and again next to my left hand on the keyboard so it feels ergonomically correct and hard to miss.