Download of InkStructure 1.3.4 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software is included in Design & Photo Tools. The actual developer of this free software for Mac is InkStructure. 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.
From the developer:
InkStructure is an application for 2D analysis of structures specially designed for engineering and architecture students. Drawing the elements in your structure is a simple process aided by guide lines that appear only when needed. Nodes are automatically added for you. You can select the desired nodes and apply external constraints to them. You can remove or edit the constraint at any moment.
You may want to check out more Mac applications, such as Cuadro or Resize Now, which might be related to InkStructure.