Many thanks Peter.
The "Venn Diagram" for the product range has never been that obvious to me, having little experience of them, so your clarification is helpful.
I see there is a "Product Matrix" at
http://www.borisfx.com/products/matrix.php, but that does not make it clear to a newbie at least that 3D Modelling is absent from Boris FX's 3D Container. The matrix does show that Boris FX has "3D Containers", "Tumble, Spin and Rotate in 3D Space", "Particle system and 3D particles", "3D Shapes including cubes, spheres and cylinders", "High-quality 3D DVE". To a newbie like me, that sounds like it does 3D generally. The Matrix does not include a row for "3D Modelling Capability..." (or "3D Arrangement...") "...in 3D Container".
I found a RED/BLUE overview-comparison at a well-known retail website (name suggestive of colour subsampling) to give a good overall flavour, because in it lists at overview level what RED and BLUE don't do as well as what they do do, hence (ignoring the possibility of unknown unknowns) one can quickly grasp their relative advantages. For the benefit of anyone else coming to this thread, I could list it here if that was OK with the forum rules.
Looks like its RED that I need.