To avoid malware or "cracked" versions that often contain security risks, always use the official channels: Visit the official website. Navigate to the Download section. Choose the V5 Trial for Windows or Mac.
Since MoI was built by the same creator, the logic is similar. Rhino offers a much longer evaluation period.
While there isn't a "free" student version, MoI 3D offers a significantly discounted . It is the exact same software as the full version but sold at a fraction of the price to anyone with a valid student ID or faculty email. To help you get started, A comparison of MoI 3D vs. Plasticity ? Where to find free NURBS models to practice with?
If your 30 days expire, you can use the "trial wrapper" which allows you to learn the tools and practice modeling indefinitely, but it disables the ability to save your work or export files. Key New Features in MoI 3D V5
Enhanced stability for complex boolean operations (filleting and joining).
You can download a version that is 100% functional for 30 days. This includes saving and exporting.