I am working on a project with a model created in Zbrush that has been provided to me for a CNC routed print. In Zbrush, the model on Subdivision Level 2 is smooth and not faceted, with roughly 200,000 polygons. Decimating the model, even to 90%, creates artifacts and distortions. Although I have exported the model as an .STL, the model still appears faceted (the low-res version) when viewed in Rhino.
Even though the model appears faceted in Rhino, a CNC test print creates a smooth model, so the problem is with Rhino and not necessarily the model we are working with. In order to subcontract the CNC routing of the model, we need to be able to view the smooth model in Rhino. What steps am I missing that are required to export the high resolution model for viewing in Rhino? We do not need the lower subdivision levels, so if deleting them is a solution we can do it.
Things I have tried:
Increasing Smooth to 1
Converting to Nurbs in Rhino
Not a specialist in CNC but that is probably because the facets are too small to notice on the printed model. Unless the g-code driver applies some smoothing to its paths.
At any rate, you are importing a mesh model into Rhino which has no information on the underlying surface. In Rhino itself, NURBS surfaces are meshed as well for display purposes but smoothing information is dirived from the surface.
The model just needs to be milled; viewing the hi-res smooth model
(subdivision level 2) in Rhino or another similar program is so that the
subcontractor will go ahead and mill it. As of now, the model appears too
faceted and they won’t take on the project. All information I can find on
the web about exporting does not address this issue, and simply "exports"
the model out of Zbrush as STL or OBJ, and then opens it in another
program. Nothing mentions a faceted low-resolution appearance or how to
increase the viewing resolution in Rhino.
You have said that the current resolution is acceptable based on the tests that you have had milled previously. Its curious that the CNC sevice provider does not understand that smooth shading a facetted model is for display only, and has no effect on the milled surface?
Interesting doc you provided. Although I haven’t tried Weld in Rhino, in Zbrush I converted all tri’s to quads, closed all holes, and used the weld command. Also, the Subdivision Level 1 in Zbrush looks exactly like the mesh I view in Rhino. Very simply, I want to view the high poly model in Rhino, but for some reason the Subdivided mesh is not “picked up” by the Rhino Software.
In the Geometry Palette in ZBrush move the slider to the highest subdivision level, then hit the Del Lower button to be sure you are exporting the highest resolution model.
Isn’t the higest resolution details in Zbrush applied with a discplacement map? I think you might need to bake the discplacement map into the mesh. Try googling “zbrush bake displacement map”.
Edit: Add Normal maps to that. You want to bake the normal maps too!
