ZBrush

this will show you how to maintain the shape and muscle definition
this all so brings out the definition.

to maintain the shape and muscle definition you had to have high subdivision level when importing it into hexagon
the problem with that is hexagon can't handle high subdivision level

if you import a Low poly model into hexagon and subdivide it then it will loses its shape and definition
the video is zbrush to hexagon and would all so work for zbrush to any other 3D App
http://www.ezbrush.mediabakers.com/zbrush-to-hexagon381.html



here is a comparison in the image below
both the same dog
both have the same poly counts
both were subdivided in hexagon 2 times
and both were not edited at all once in hexagon.

look what the subdivision did to the dog on the right
he lose his shape because the subdivision smoothed him
and he lost his muscle definition because that was all so smoothed by the subdivision.

in other words you can have a low poly count dog and only need to subdivide him once or twice
and he will keep high details of a very high poly count dog



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