What (like bridge design or Civil 3D integration) you are looking to perform?
Autodesk InfraWorks 2021 is not available as a standard "free" perpetual version, but you can access it legally for free through specific Autodesk programs. Official Ways to Get InfraWorks for Free 2021 download autodesk inc infraworks free
If the Autodesk options don't suit your situation, several free or low-cost alternatives might meet your infrastructure design needs. What (like bridge design or Civil 3D integration)
10 GB of free hard drive space for installation, plus extra space for local model caches. The Risks of Third-Party "Free Download" Sites 10 GB of free hard drive space for
from Autodesk's official site to test its capabilities for a limited term (typically 30 days). Educational Access
Autodesk does not offer a free, perpetual license for 2021 software to the general public. However, there are legitimate avenues to access the software: 1. Autodesk Education Access (Students and Educators)
Autodesk does not provide completely free, unrestricted lifetime versions of its commercial software. However, there are several official, legal avenues to download and use InfraWorks 2021 without upfront costs. 1. Autodesk Free Trial