Variables and expressions are something that we’re working on as we speak and will be released in a few months. They’re indeed useful for such use cases – that’s why we’re adding them.
Until then, many of the simpler situations (such as halves, thirds etc.) can be used with some geometrics. For this particular case you could add three construction lines that are constrainted to be:
- tangent to each other
- perpendicular to the edges of the body
- of equal length
If that’s all set, the application will automatically calculate the sizes so that each segment would be 1/3rd in size of the edge and then your tenon can be aligned/constrainted to that.
geometric third.shapr (7.4 KB)
It’s trivial to do it for halves (we offer the halfpoints of the edges for snapping), the steps above are good for thirds, quarters are a repeat of the halving – but I admit, for smaller subdivisions and for arbitrary percentages this approach is not working well.