upload them in here. Press "go advanced" button, manage attachments and upload them here. Your clouds look cool however, rendering of environments are too lose so that it sticks out in a bad way. Clouds seem like u made them from real photos whereas your cities are flat and done very quick. I don't see a focal point either.
These are as generic as sci fi environments can be, not that it's a bad thing, but try to stretch yourself creatively. Im sure you have seen movies like, blade runner, predator, and riddick. Each of these movies are sci fi themed, but drastically different in style. I would say to study/ practice perspective/ how light reacts to objects, and basic forms/ silhouettes.
There really doesn't seem to be any focal point, so I would say to look up the rule of thirds. Although this is very basic stuff, it does help to create focal points in concept art. Eventually, you'll do it without even knowing it.
Yes, i painted the sky clouds with real photos and brushes, a mix of them.
I take note about the focal point, and i´ll try to make more creative and personal scenes.
very thanks for your comments and advices, thats is exactly what i´m looking for.
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