hi hifred, you got the point there that clearly explain the biggest weakness of SubD modelling, long time ago, when we are still using traditional SubD that doesnt really support ‘Hard Surface Modelling’ (we call it by that name, a type of geometry with lots of “trimming” and shard edges with combination of smooth curvature) .
the traditional way of doing hard surface is model your “base level” (Level 0) geometry, once you are satistfied, boolean limit surface until you please. with history chain on, you can interactively change your “cutter” object and see the boolean result updated. however, those are not efficient as we will have performance issue due to history stack.
things have changed since 2000, when modern tool for poly has been implemented in polymodeller software such as Maya,3ds, etc. on my previous post I was afraid that RHino subD modelling will not have this “modern” tool instead still relying on traditional way which then leads to one of the biggest problem as you have mentioned on your example.
I tried to do that in Maya (but u can get the same result using 3dsmax or any other poly modeller software).
I have downloaded your file around this time (my local time) about 9PM at night, and I finish everything around 11:30 and took me 30minute to compile some printscreen and adding shader + antialiasing for you to have a better look.
and I have to rebuild the whole model from scratch because I am using OpenSubDiv to minimize edge loops. and topology wise it is different from your provided mesh, so the total time to build the model from scratch until finish is about 2.5 hours, if you have wacom you can do it faster though. (my wacom is at the office, I am using my old 4GB ram Laptop for browsing kitten video on Youtube)
what I am trying to say is that with modern poly tool this hard surface modelling will be easier to tackle.
I will explain it in a while, but first, for anyone who read this post, please dont be offended if I dont use Rhino for the sake of this discussion, this is for study purposes and we are trying to get the best out of other resourches for RHino to improve., also pardon my Broken english…
so this is the result that I got, as you can see I am using OpenSubDiv with Controlled Crease (crease set node that is plugged into the Mesh), Setting limit surface to level 4 (iteration 4) so I need to use crease value no higher than [3.5].
the advantage of using Opensubdiv is that I dont even have to subdivide my geometry for rendering purpose, Rendering engine that support OpenSubDiv will tesselate that to become smaller than 1 pixel so interms of computer graphic, there is no such thing as jagged face no matter how far I zoom in to the viewport.
and here is the control Cage, of course it is denser than your original control cage, but this is the consequences of SubD, and there is a massive set of tool to manipulate these control cage with ease, we call that deformer (maya) or Space warp/local modifier (Max). and our translate gizmo (Gumball in rhino) is equipped with additional feature to make sure continuity is maintained.
I use QuadDraw. to make sure my mesh stays as close as possible to your original design. and some Deformer to conform my control cage to your original mesh, that means I can control curvature smoothness without having to move my vertex in 3dspace, I just need to worry about topology.
and I didnt use any Sculpting tool in Maya as I dont have my Wacom here at my tiny apartment
here is some set of deformer that is handy to modify control cage, it can make a dense mesh behave like low-res mesh.u might recognize some I believe as you are very familiar with SubD.
and lastly checking whether the model has Ngon or Triangular face=
total face for level 0 is 614, which is considerably low if you want to further edit this shape. (to whatever shape you like)
now, since you are a product designer (correct me if I am wrong) you will still need rhino to rebuild the model in NURBS if you want your model has micron-size precision (perhaps having those clip-lock detail (I dunno what to call that in english) that relies on precision to get it to work. SubDs are mainly used for form finding and design stage. however it is extremely easy to convert this model to NURBS as the model consist of QUads. and there isnt any “weird” topology.
I do apologize if my english confuses you, and again, please dont get offended if I post a printscreen of other software beside rhino. because I use rhino purely for its grashopper and robust NURBS tool that I dont find in any other software.
peace and Xie Xie for reading
edit= I am only active during the weekend so I can only read this forum on my phone for the next week as I will be having business trip (more like paid vacation, yeyyyy), so if you post some image, I might not be able to open it in my jurrasic Phone. so again, pardon if somebody ask smthing and I cant reply…