Hi Radomir

Thanks for reaching out to the Lucid community! Unfortunately you can only set measurements by clicking and dragging. If you are having trouble setting a specific length I would recommend zooming in further which will give you more granular control. If you would like to pass the idea of exact measurements on to our development team for their consideration please add it to our feature request form here. Thank you.

does the requested feature above still not exist (entering exact measurements)? 

Hi Steve

Thanks for following up!

The feature has not yet been implemented. Note that the more requests we receive for it the higher the chances that it is added to the Product team's roadmap and for this reason I encourage you to send them feedback too via our feedback request form.

I apologise for any inconvenience caused and thank you for your feedback!