LEDAS RhinoWorks 2.0 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the software is LEDAS Ltd.
The following version: 2.0 is the most frequently downloaded one by the program users. The software is included in Photo & Graphics Tools. We cannot guarantee that the program is safe to download as it will be downloaded from the developer's website. Before launching the program, check it with any free antivirus software.
From the developer:
RhinoWorks is a plug-in that brings constraint-based parametric design in Rhino. A constraint specifies geometric and dimensional properties of one or more shapes. Applying constraints forces geometric bodies to change their shapes or/and position in 3D space.
You may want to check out more software, such as Ledas 2D Geometric Solver or LEDAS 3D Geometric Solver, which might be related to LEDAS RhinoWorks.