You described my process correctly. When I created the image, my focus was primarily on the matching the color palette of the VG studio image. I was aware of the staircases but I wasn’t actively trying to minimize them. I can certainly see why downsampling would make the staircase effect more prominent.
I tried some of your suggestions of using the full res data and growing the segment before using SplitVolume. I would argue that the results are not necessarily better.
First, here’s the downsample data where I grew the segment before using SplitVolume
As you can see, the staircase effect is reduced but some definition is arguable lost but overall I think it’s an improvement.
Now, here’s when I used the SplitVolume on the full resolution data without growing the segment.
The image is very sharp! However, the staircase effect is still there. The steps have just been made smaller.
Lastly, the full resolution data with segment grown before spliting
It’s better but I’m not sure that it’s great. I was hoping to see something more similar to the first image up top with the down sampled data and a grown segment, but with more definition. Here, the staircase effect is reduced but still present. However, overall I still think this is a great rendering and better than when I didn’t grow the segment before using SplitVolume.
I personally didn’t notice any difference when setting the quality to Maximum vs Normal vs Adaptive.