continuing from here
if you make a snapshot that includes only material changes, then it is not possible to render that snapshot using Render Settings > View > Snapshot; you will get this error box when you use RenderSourceView:
to fix this, you will have to remake the snapshot with camera included
however, this defeats a primary workflow that people would like to implement using snapshots: to have different materials/assignments for different renderers, and switch between them using snapshots
this could be worked around by including a camera in each snapshot, but it would be tedious, since in practice, you are going to be having different views over time, and would need to be continually restoring & overwriting the camera in each snapshot
so I think the behavior should be changed – it is possible to restore a snapshot that includes no camera via the snapshots panel, and it should also be possible to render one, with the same behavior: the current view is not altered, but the materials/assignments are applied
and here, I also have a wish: to add a snapshot category for the material (and maybe other) list tags filter; if this was added, then you would truly have a workable way of switching between renderers, since each renderer can include a tag when its render contents are created, and this new snapshot category would allow completely switching between different renderer “views” of the model