EzCAD is a powerful CAD that works like drawing components.
These components can be used on the following development environments:
Borland Delphi (from 4 to 7),
Soon in Kylix.
Delphi you get full source code on purchase registration.
EzCAD is widely documented on these three sources:
Reference Guide,
Developers Guide, and
Tutorial
If you want to be convinced by yourself, download the components trial version in your language, together with the demos and data, with which you can be able to fully evaluate and take your decision.
On the evaluation time, if you have any doubts, don't hesitate to contact us, and we will do our best in order to help you.