Keep having this annoying Sketchup problem. Sometimes I can make an object on a face and it doesn’t work. Had that specific problem when I wanted to sink a hole through the side of the nightstand for the CPAP hose.
Decided to try and watch some tutorial videos and figure out what’s the issue. Trouble was I didn’t know what to call the problem in order to search for a solution. Finally found a video which describes it as “Z-Fighting”. The video is SketchUp won't create a face where I want it to . Here’s a related video with the same stuff.
Here’s the end result – a hole that works.
