As stated here, there is a pretty big difference between an NDA/ CDA and a patent. There are also a few versions of NDA/CDAs, a one way to the company or from the company and a two way. Comapnies can provide information to and from each other in a two way NDA without much worry that their information will be shared to other people outside the agreement. In a one way, one company is providing information to the other in order to do something, like create a quote for a design job. Essentially they NDA will allow companies to communicate freely with each other with proprietary/ company secrets in order to conduct business.