I suspect there’s been requests for this already, I’ve seen a few post related to creasing but not sure how related to this they are.
I am fairly new to Rhino, I’m trying to implement the software into my workflow. One thing I use often in other apps is the ability to moderate the intensity of the crease on an edge. Been looking around everywhere online to see if it’s possible in Rhino 7 but it seems like it’s not.
So that’s a big wish for me.
B.T.W. My second big wish was constraints, and they look promising as hell right now! Now, if something like this could exist on a component level, it would be like heaven on earth.
“Crease” in Rhino has a specific meaning of a sharp break in smoothness of a surface. Along a crease the tangent direction is not unique - it depends on the side of the crease. Crease in Rhino is used mostly in SubD modeling. In Rhino “kink” is usually used for sharp break in smoothness of a NURBS surface. In Rhino if there is not a break in the smoothness then it is not a crease.
@Andre_Michaud By “moderate the intensity” do you mean smooth the crease by replacing the crease with a rounded area? Are you modeling using SubD, meshes or NURBS?
Are you modeling using NURBS, SubD or meshes? Also do you want to modify the actual geometry or only the appearance in renders of the creases?
@dalelear When ToNURBS is used on SubD with intermediate sharpness edges will the resulting NURBS surfaces be rational or non-rational? My strong preference would be for the results to be non-rational.
There are no changes to the way SubD to NURBS conversions work.
The ToNurbs command will continue to create non-rational cubic NURBS surfaces.
The ExtractWireframe command will continue to create non-rational cubic NURBS curves.
Away from extraordinary vertices, the conversion to NURBS is geometrically exact.
Near extraordinary vertices the NURBS conversion is approximate.
This behavior is identical to the SubD to NURBS conversions in Rhino 7 and Rhino 8.0.
The NURBS patch density is higher near sharp edges.
The Rhino SubD sharp edges algorithm is the industry standard Catmull- Clark subdivision surface sharp edge algorithm described in Section 3 of Subdivision in Surfaces Character Animation. Rhino’s version assigns a sharpness value to each end of an edge (the citation above assigned a single value to an entire edge.) For edges with constant sharpness, the Rhino SubD result is identical to what is described in the citation. For variable sharpness edge chains, the Rhino SubD result is similar but has slightly better curvature behavior in common modeling situations. Rhino’s approach also permits a single edge to have variable sharpness.
SubD surface tangent and curvature are continuous across smooth and sharp edges.
The user experience is to select edges and assign sharpness at vertices in the chain. These user supplied values are used to set the edge-by-edge sharpness values.
You may follow the development progress by looking at these Rhino YouTrack issues.
SubD sharp edges are scheduled to be in Rhino 8.
We do not know when Rhino 8 will ship.
If you have a license to use Rhino 7, then you can experiment with the present prototype code in the Rhino 8 WIP. I suggest you wait until on or after Wednesday, March 8 to begin as some important fixes were made this week.
I apologize for my confusion and posting incorrect information.
I’m liking the new feature for edges. It’ll save me a lot of time in many cases. Is it possible to have a real time dialog box similar to ‘Blend Surfaces’ where one can control the amount of sharpness in real time?
The Rhino 8 WIP we published March 14, 2023 is the first Rhino 8 WIP with a somewhat usable command for creating and editing sharp SubD edges.
NOTE WELL:
Rhino 8 WIP saves Rhino 8 files and Rhino 7 cannot read Rhino 8 files. Do not use Rhino 8 WIP if your customers, your colleagues, or your workflow requires using Rhino 7.
This enhancement is definitely a work in progress. We’ve done our best to make it somewhat usable but the code may be unstable.
utstanding!!
