The version you're interested in is T-Splines v.4.0.r11183. This version likely includes various features, bug fixes, and improvements over its predecessors.
Convert the T-Splines geometry into standard STEP or IGES files. This bakes the shapes into traditional NURBS surfaces that any modern CAD package can read. t-splines - v.4.0.r11183 download
Alongside the core modeling improvements, T‑Splines 4.0 also featured an optimized rendering pipeline. The new version reduces the overhead when converting T‑Spline surfaces to NURBS for rendering or export, resulting in noticeably faster viewport updates and final renders. Additionally, the plugin was tightly integrated into Rhino 5’s interface, making it feel like a native part of the software rather than an afterthought. The version you're interested in is T-Splines v
If you cannot safely acquire or run T-Splines v4.0.r11183, the 3D industry has evolved to offer native, highly capable alternatives that eliminate the need for legacy plug-ins. 1. Rhino 7 and Rhino 8 Native SubD This bakes the shapes into traditional NURBS surfaces
Because Autodesk has discontinued sales and distribution of the Rhino plugin, you cannot download T‑Splines 4.0 from the official Autodesk website in the same way you would for an actively supported product. However, the software remains available from a number of archival and community sources.
T-splines have found applications in various fields: