Simplify a complicated mesh for export as an STL ok so basically, I’m trying to make a mesh for the purposes of 3D printing. I started with an imported stl file and then did a bunch of sculpting to shape areas how I wanted. This has made the blender file huge and my computer hates me. Anyway I finally managed to get it to a stage where I could export the model as an stl file, however when my 3D printing software tries to process it can’t because the model has these points with an absurdly high concentration of vertices around the sculpting areas (most of it now essentially ‘inside’ the mesh). If I try to decimate the model or merge by distance its basically impossible to keep the overall quality. Is there any easy way just to make a new mesh using the ‘outside’ shape of the model? This will then be simplified and my 3D printing software will probably be able to handle it?
Thanks for anyone’s time who has read this
I agree with Jachym.   The remesh modifier may do the trick.   

In object-mode, select Modifiers, and add the Remesh modifier.  Find the Octree Depth Option (it will be the main one for your issue) and adjust it up or down.  Careful! With high poly-counts like you have - adjusting it higher may cause Blender to crash so take the necessary precautions with this in mind.

See this vid at the 1:30 timeframe to see it in action.

https://video.search.yahoo.com/yhs/search?fr=yhs-symantec-ext_onb&amp;hsimp=yhs-ext_onb&amp;hspart=symantec&amp;p=tutor4u+blender+text#id=5&amp;vid=79e85e222216fa41a1ec00cee407affe&amp;action=view