Download of 3DimViewer 3.1.1 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. 3DimViewer for Mac lies within Design & Photo Tools, more precisely Viewers & Editors. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free software for Mac OS X is an intellectual property of 3Dim Laboratory.
From the developer:
3DimViewer is a lightweight 3D viewer of medical DICOM datasets distributed as an open source software program. The viewer is multiplatform software written in C++. The application works as a handy 3D viewer of volumetric data. It provides multiplanar and orthogonal XY, XZ, and YZ views.
You may want to check out more software for Mac, such as TVPaint Animation, Cuadro or Web-Image-Collector, which might be related to 3DimViewer.