The right image looks like you are in the "user" view which is normally ortographic. These errors look like z-fighting in the viewport. Maybe because of the ortographic view.
@bibendum: no it's because we're viewing it from the end-user perspective, while you're viewing from the buiding-process side. I get your point though.
As a modeler I suggest more views to model from. The perspective shots are limited and need more help with scale. Front , Side , 2.5 view and reference scale
That is already the UW view, that is the reason why it shows the elongated UVs that highlight the problem. The problematic verts are pins created by the quick peel. This how looks in UV view
As @Steppenwolf advised, block out in 3d from your top view based on your sketch........and then let the magic of 3d take you to the left/front view...... :)
i don't know if this has been brought up. when viewing in IE, the banner is centred, but when viewing in firefox, it's left aligned. other than that, it's schweet.
From that point of view, the arms look a bit long. Meaning the lower bit. Perhaps it's the view plus their bend, but also the fingers look too short. :S
I can finally show the breakdown as I needed to wait for 80 Level to publish the article. Here's the link to the article: https://80.lv/articles/a-step-by-step-guide-on-recreating-venice-city-view-in-ue5/ And here's the breakdown for ArtStation as well: https://www.artstation.com/artwork/XJnOKy
Why are you trying to render a realtime mesh with mentalRay? You should try to view it in DX view or a game engine. The flipped green channel is a mentalRay shader problem i think. At least in 3dsMax.