Hello everyone, when converting STL to Nurbs is it normal to lose quality? Is there another way to make the STL editable in Rhino?
No.
Yes
Mesh to Nurbs
(don t use _toNurbs directly on a complex mesh !!!)
search for reverse engineering in this forum.
there is two approaches in Rhino - that also can be combined:
(1) directly remodel nurbs surfaces
(2) mesh → Quadremesh → SubD → Nurbs see here
Mesh Edit
there is a lot of approaches to deform / modify control points / mesh vertices.
check all kinds of transform tools.
check UDT
special stuff for meshes here:
https://docs.mcneel.com/rhino/7/help/en-us/index.htm#seealso/sak_meshtools.htm
if you need more input - please give a example file / more detailed question / point to the details that you struggle with.
kind regards
-tom
3 Likes
Yes, it is normal. A polygonal representation is always “less” than a mathematically described model using parametric equations (in this case, “Nurbs” surfaces).
Using Sub-D’s is a dirty hack, sometimes this works. It depends on where your model comes from and how well it was modeled. A proper class-A model, exported only as polygons, cannot be regenerated automatically with the same quality. However, if you never had a surface model before, a “bad” Sub-D model is better than nothing. So it always depends… But always think also about that polygonal data, like coming from a scan, might also contain errors. It should not be in your interessed to simply keep those errors. So proper remodeling from scratch, is technically often the better solution.
1 Like