Impact Craters - form study

Various impact crater starting points;
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These two files need some interior geometry cleanup but are printable:
crater_impact.stl
crater_impact_side_access.stl
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They are meant to be inset onto blue foam since the depth of the hole is lower then the debris along the ring.
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Feel free to splice and modify; they are far from perfect and could use some fine tuning in zBrush/Sculptris/Mudbox