Hi I have seen many requests for a cancel/escape key.
I understand that in those very intense computing loops needed for the complex operations involved in 3D model/edit you will never include a keyboard check. It will slow down processes to an unacceptable level.
Here is my suggestion:
Instead of needing to check keyboard you can implement an interruption controller for the ctrl-break and use it to stop the operation running.
This will keep the main loop clean from slow code and give the chance to stop "forever lasting" operations that we poor ignorant undeucated users sometimes start by mistake due to our lack of ability.
Thanks for listening