Quote - Since Bryce uses its own render engine, if you save the scene out and use an external renderer to render it , can the rendered scene and the scene parameters still be recognized by Bryce and brought back into Bryce for later readjusting?

Bryce has its own propritary format for it's files, so you cannot use an external renderer directly - however if you export your scene to an OBJ file - which should be possible with the u tag on boolean objects. then you can render it with an external renderer that supports the OBJ format. Another approach could be to import the OBJ file into another 3D application (3DMax, Blender, C4D or whatever - most 3D programs today supports OBJ format) - Many of these then have Exporters for different renderengines - the 3D package i know the best is C4D - and there have been made a bunch of exporters for various render engines (VRay, Indigo, Octane, Thea, Finale RenderStage, Luxrender, Fry and Arion render) - I know theres made a lot of exporters to blender as well, to freeware render engines, and i think that there is a native exporter for Luxrender wich is a freeware unbiased photorealistic renderer - phew ...that was a lot :-)