Gunstruction is an online virtual rifle builder. It uses a rendering engine via an application that runs through your internet browser. So there is no software that is downloaded. It has virtual components from many manufacturers. The virtual builder allows you to choose whatever part you desire and build your rifle. Gunstruction then takes it a step further. They keep track of all the components you have used in your virtual build. They even have links for you to order the parts that you have chosen. The program allows you to take snapshots of your virtual build and share it on social media.
Recently, Clint Terrill of Motus has used Gunstruction to preplan a rifle build. Then he ordered the parts and completed his actual rifle. Here is the article about the build.
Here is the virtual build.