Following bejant's indications I downloaded CamStudio and Handbrake from sourceforge onto my Win8.1 notebook and, after a bit of learning, produced a first brief video showing the animation of the dual cylinder version of my Vertical Engine. Here is a link to the mp4 file on DropBox. Thank you again bejant!
https://www.dropbox.com/s/kc70g97lj7xqs ... n.mp4?dl=0
In the meantime I have produced three A4 pages showing simple views with dimensions of the more than 20 types of part needed for building the reversing mecchanisms. I tried to use the technique suggested in at least two threads started by newbie FreeCADers like me who had made a 3D model but were having difficulty with generating the production documentation. The replies in these threads admit that FreeCAD's current support for generating documentation from 3D model is rather weak and suggest using FreeCAD's Drawing or Document WB to create Page objects with the needed views without dimensions and export these pages as DXF files and then use a 2D CAD program like LibreCAD to add the dimensions and the text. The approach worked well enough for my home workshop purposes but my three documents would not be usable by an external fabrication facility - information is missing due, as far as I can see, to limitations in FreeCAD's ability to export to DXF.
- Hidden lines, which show on the FreeCAD screen, dont turn up on the LibreCAD screen. So, for example, the depth of a blind hole or a recess doesn't show on any projection.
- The projection of circles onto a view plane not normal or parallel to the plane containing the circle can produce an ellipse with the wrong inclination. This makes it impractical to show isometric views of any part containing features with circular edges.
I love FreeCAD's marvelous support for 3D modelling and animation. But, for many potential user's, once the 3D model is completed, it must be used as the reference source for generating production documents. So I feel that improving FreeCAD's support for this perhaps unglamorous activity is very very important for FreeCAD's future. Please dont take this as a criticism.
A final remark relating to the first post of this thread. As reported there, when making the 3D model I gave the individual models of single parts increasing values for their X and Z Placement values in order that there would be no overlapping when viewing all the parts together from any of the six standard viewpoints (Front, Left, Back,---). This was a technique I had used with models done with AutoCAD to facilitate the production of the production documentation. However with FreeCAD it proved to be a mistake because I found great difficulty in locating (X and Y values) the particular part I wanted for a particular Drawing View. So in the end I gave Placements of (0,0,0) to all the parts and used their Visibility attributes to make sure that only one was visible at a time.