What is it about your designs that is so special that you're concerned about their security.
I use OnShape. Its professional plan is $2100/yr, however they offer it for free with one limitation-your designs are public. Do I care if someone steals my design for a hall table or vanity? Nope.
I use OnShape. Its professional plan is $2100/yr, however they offer it for free with one limitation-your designs are public. Do I care if someone steals my design for a hall table or vanity? Nope.