Building a new bike never starts from scratch
I always start from an older bike
Measuring the old bike, and importing these dimensions into Bikecad takes a lot of time
Not in the least because angles are difficult to measure
That is why I have to measure a lot of diagonal dimensions.
Manu dimensions In Bikecad start from the saddle.
I think the saddle is not a good starting point to take measures from an older bike
The saddle is not flat, it is placed for and aft, etc
And there is always the very difficult to know Saddle reference point X and Y in Bikecad.
My life would be much easier if I could take measurements from the Saddle clamp instead.
Saddle clamp to BB X and Y are already there.
In addition I want to propose:
Saddke clamp both to top and bottom of Head tube
Saddle clamp of ground
BB both to top and bottom of Head tube
Top of Head tube off ground
Thanks for the suggestion for additional dimensions. I will plan to add these to the next update of BikeCAD. However, I should point out that one of your requests is already included. If you're looking for BB to top of head tube. This is already available in the form of stack and reach. These are found in the Frame tab of the dimensions dialog box. You can also directly input stack and reach in the Primary dimensions dialog box as described at: bikecad.ca/toptube_frontcenter.
BB to bottom of the head tube is available in the form of dimension: Head tube bottom. There are various forms of this dimension, but all are available in the Jig setup tab of the dimensions dialog box.