I have been getting excellent results with Veras Version 6 and see that the artifacts generated in the Refine feature of Version 5 are gone in Version 6. Now what I think would be very helpful in the Refine feature is that it use the original, uploaded image as the ‘seed’ if that’s the right term, for areas selected by the blue bounding lines for re-rendering rather than the already rendered image. In my experience areas of the image you want to ‘correct’ within the blue line boundary are typically altogether different from the effect sought, constitute an error if you like. For instance what was supposed to be a lawn has been rendered as water - or the other way around, water has been rendered as grass. At the same time what seems to happen is that objects present in the original Sketchup drawing get ‘dropped’ in the rendered image. No amount of re-rendering in Refine can recover them. Now if the blue bounded region selected for re-rendering referenced the original Sketchup image then these dropped objects could be recovered. As well by localizing the re-render boundary to just say a grass lawn, you could coerce back to grass what had been rendered as water.
Now with the system as it is, you can approximate this strategy by piecemeal rendering different areas of the original Sketchup image, that is, starting out with the Refine feature bypassing ‘compose’. What I think would be extremely useful is to go at it the other way: Render everything in compose, then piecemeal recover portions of the original Sketchup drawing which Veras has incorrectly rendered.