Hey I’m in the process of working through the level 1 training and i found 1 bug and 1 annoyance in chapter 70 “dimensioning the model”
First the object to be dimensioned has a hole cut in it which is supposed to be circular but isn’t and the radial and diameter dimensions get wierded out by that, circles and arcs work fine though, so it’s more of a inconsistency of how the modell was set up and every new user going through the level 1 training in rhino 6 will see this.
The other thing is an actual bug where in perspective viewport if you do a dimension there is like an invisible rectangle in the backgroud blocking the renderes preview of the dimension, adding the dimension with left-click works fine.
the file in question is Dimension.3dm (331.0 KB) but its unaltered from your site.