netfabb basic is a free utility to review and fix your STL files before sending them to a 3D print house. You can get it here: http://www.netfabb.com/downloadcenter.php?basic=1
I have been checking it out to fix STL errors in my models, but learned something interesting when I exported the result.
First, a little background: If your model has curves and you want them smooth, you can either set the ACIS Faceter Quality to maximum or you can specify the Expert Faceter Parameters. Setting Normal Tolerance to a smaller number creates larger, more accurate, files (it specifies the allowable difference between the actual angle of a point on a surface and the value when a flat polygon is used to approximate the surface in that area).
When you export a part from netfabb, you can specify the tolerance as distance instead of angle. This allows you to adjust the model to your finish requirements, or to the print service you will be using.
I specified the tolerance as 0.001 (inches, in my case, because that's what I was using) and could not see a difference in the resulting image. The file size, however, dropped from 89 MB to 27 MB. As several 3D Print Services have file size limitations, this could be quite useful in getting your models under the limit.
You can, of course, adjust the ACIS parameters in TurboCAD before saving as STL, but the settings do not allow you to specify the tolerance as distance (which, to me, is more understandable than angle).
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