Help reducing triangles

[SGoldthwaite]

I have an STL that I want to bring into Fusion 360, but it has almost 1.4 million triangles so it bogs Fusion down.  I want to reduce the number of triangles while still keeping the shape.  I attached a picture of the STL.  It's a lot of wavy curves.  I want to keep the crests and valleys pretty sharp.  I have Meshmixer, but don't really know how to use it.  I'd appreciate some tips on reducing the triangle count for this particular shape. 

[hfcandrew]

In Meshmixer use Reduce: https://help.autodesk.com/view/MSHMXR/2019/ENU/?guid=GUID-54087649-E962-409E-8565-F646BDA80B33

So it doesn't decimate import geometry generate facegroups first:

https://help.autodesk.com/view/MSHMXR/2019/ENU/?guid=GUID-5E91C94A-1D1B-46D4-BF09-776BE74F12A3

[SGoldthwaite]

Thanks.  I used the reduce feature with Max Deviation option and set it to 0.01mm.  I also enabled shape preserving.  This reduced the triangles from 1.4 million to 14,000.  The STL looks very good and is much more manageable in Fusion.