Strut 1.6 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The actual developer of this free Mac application is Barrington Expeditions Limited. Strut for Mac lies within Design & Photo Tools, more precisely 3D Modeling.
From the developer:
Strut is a free app that lets architects, engineers, owners, and construction professionals easily access full 3D models of their buildings from any device. You can upload your 3D model from your computer or cloud storage and it will instantly sync to all of your team's iPhones and iPads in real time.
You may want to check out more Mac applications, such as TurboLayout, which might be related to Strut.