Not sure my subject is correct as I'm fairly new to this. 

I want to get an object 3D scanned and then make the file available for purchase and download.

Is it possible to keep the buyer from then selling or giving out that file to others?

Thanks EVERYONE Companies that want to protect their business software usually pair the software with hardware keys that have to be present connected to the system either (RS-232 Serial, USB, or Parallel Port ) for the software to operate. However anything can be reverse engineered and hacked/cracked.

Probably the most secure would be a software that requires a handshake to your authentication server and if the handshake broken the software stops working. But offline users might not like that. Many online games that are pay to play have this model of piracy prevention. However as an example. Blizzard that made world of warcraft uses this model however people made private servers that pair with their software and the software then runs as if it is connected to Blizzard when it is not. This authentication with internet connection would be better at preventing it being sold as used to someone else, however if someone sold the software with their username and password. It would be difficult to track this down as for you probably wouldnt want the software to break if all of a sudden their IP Address changes etc and IP Address can be used as a method of tracking based on retrieving a traceroute result and if all of a sudden its authenticated on the west coast vs east coast and the software ISNT suppose to be on a mobile computer but instead a server that is in a fixed location you could DISABLE the software from functioning based on the traceroute feedback result.

But if anyone is able to gain access to your source code and alter the program can get around all kinds of checks by a process of decompiling code and making alterations and then recompiling the code. However memory injection is a common attack method where the address is known to force a value to to make the software happy as well as DLL alterations which end up passed around as cracks.This has got some suggestions https://www.copyrighted.com/blog/image-protection-online

My suggestion is to make the purchase so cheap like $2.00 and so easy to pay the majority of people will just pay for the convenience. It could be a good idea to get an email address for each purchase so you can then market other images direct or start a email newsletter. Most people want to reward effort if the price is right. I like Lisa's suggestion of if its possible to make it low cost your likely to get people to buy into it because the cost to be legal is inexpensive, so people are more likely to buy something vs finding a way to crack it to get around PAYING because price is too much to them.