SubD to Nurbs - clean surface?

Sure, here is one:

This does not change the geometry of the underlying surface, so edges (or what would be an egde if the faces were unpacked) will stay the same as with unpacked faces. However, it will be easier to keep the surface smooth as you further edit it, given that whenever possible merging faces reduces the CV count. This thread has a dramatic example of how much that can simplify the CV hull.

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Super interesting, thank you for the information!

Blenderā€™s subdivision surfaces will soon get a ā€œmore compatibleā€ toggle switch (I think theyā€™re calling it ā€œkeep edgesā€ or something), so I really want to experiment more with editing in Blender and converting it in Rhino (we already completed one project using that method, but it was an art project that was milled in foam/stone so it didnā€™t require any precision surfacing anyway).

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In this example packing didnā€™t work @27400 subD faces.
[it is not that this particular mesh geometry needs such high subD face count, but were I to have add some ornamentation as I usually doā€¦ high face count would have been necessary ]

Here with 17500 faces it worked well.

thanks a lot
Akash

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While I understand the counting of CVs. I find the the number of Nurbs surfaces is critical in trying to transfer these models to engineering programs. The reduction in the number of surfaces here can be staggering.

Here. Right to left :
Imported Zbrushā€™s app asset, female demo-head low poly [forgot the eyesā€¦ sorry]
SubD 1/1 conversion.
Nurbs conversion

looks very good in most areas.
Hopefully weā€™ll get in the future an option to draw guide curves to help the topology flow better.
I can see no loss of form which is very good.

some problem areas in the neck mostlyā€¦

thanks a lot
Akash

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Here I tried to add some simple curving details to see if this can make it into Nurbsā€¦
This doesnā€™t work at this pointā€¦ as far as I could manage,
would love to know if there is a way?

One way I would imagine this could possibly work
[ without needing a monster computer with 200GB of rams or something] Is to have a way to mark [perhaps paint a boundary line] around a specific area in the mesh that needs higher details. then have the quadremesher, create a much denser subd within the boundary, while keeping the rest of the geometry low enough face count.

Or perhaps a [smart] algorithm that recognise small details and build small faces where needed [auto subdivide these areas of the subD]

thanks a lot
Akash

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how crazy are you zbrush models? are they relatively mechanical parts, or are they insanely detailed 200million poly models with micro textures on everything?

throw up a typical example and Iā€™ll give it a goā€¦

my thought is that exporting a quad dominant model from zbrush may convert to subd as long as you are not bringing in 200 million polysā€¦

if so, then decimate it in ZB, then bring it into rhino and quadremesh it and try the nurbs conversion/ pack from there. Iā€™d prefer you burn up your cpu testing this instead of mine, but Iā€™m game to give it a goā€¦ Iā€™ll keep the extinguisher handyā€¦

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Yeap, you could do it that way. Or wait for the details to be Curves on the Polysurface solid and use the PanelEdges capability to have dynamic details on the polysurface.

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Hi
Is this command available in the WIP already? I canā€™t find it.
rhino say unknown commandā€¦?

thanks a lot
Akash

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Passed on Rhino WIP for Windows (7.0.20248.23555, 9/4/2020).
Passed on Rhino WIP for Mac Version 7 WIP (7.0.20248.08006, 2020-09-04).



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Thanks @inju
I see you have a newer version then mineā€¦?
I have 20245. from last Wednesday. and you have 20248.
Strange as Iā€™m getting the < your version is the newest one available > massage.
Are you on a VIP build? [daily version]

thanks a lot
Akash

Yes.

Hi Scott, Sorry I donā€™t understand what you mean here?

thanks a lot
Akash

I am sorry I was not clear. It is officially called shut lines : https://docs.mcneel.com/rhino/6/help/en-us/properties/shutlining.htm

It might work too modify the object after converting it to NURBS.

Hi Kyle
Thanks for volunteering to sacrifice your hi-preformance computer on the altar of TechSupport.
As my 2013 MBP does not even qualify for minimum hardware requirement.

Iā€™m still finding out and learning the Rhino & Zbrush pipeline
I try to do the jewellery body [main parts] in Rhino as long as that makes sense, and then send to Zbrush for sculpting / ornamentation / engraving. Basically just doing on the computer the sort of work I used to do by hand directly on hand fabricated gold part.

Havenā€™t used Nano Mesh or HD geometry in ZB yetā€¦ so parts can go up to 20 million perhaps for the required resolution.
and yes, it then can be Decimated a lot without losing any details.

So the big wish is if there was a way to bring Quadremsher in Rhino to take the decimated geo, and convert to SubD using the same idea! meaning large faces where possible, and very small [subdivided] faces in the areas of small details.

Here from hi poly


to Decimated geo with dens areas where small details are

unfortunately Zbrush does not maintain quad geo when decimating. But rhino could do it! as subD have no problem with Ngeons so the border between the dens details and the large faces is [in my user logic] possible.

thanks a lot
Akash

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Hi Scott
I tried to experiment with shut lines [first time thanks for opening that door] But Iā€™m not sure how this can be of use in my workā€¦ itā€™s a render mesh thing, so it does not actually being applied to the nurbs part.
For curving in mesh, ZB, is no match really. this is one of the main reasons I work with it together with Rhino.

thanks a lot

Try the extractrendermesh command and you should get the modified mesh.

This is just experimenting with workflow. When are NURBS required and when are meshes required? What is the final fabrication technique?

All this new tech allows us to go back and forth much easier then before. But it also creates a lot of questions about the most efficient workflows.

Apology, my last reply may have not been written well.
I canā€™t at this time imagine a scenario in my work where I would want to modify mesh in rhino [apart from quadremeshing to subD] I have access to ZB so why would I want to struggle in rhino when it comes to things like ornamental engravingsā€¦?
The issue I raised these questions was in regards to arriving at the optimum way of getting the ornamented mesh into rhino Nurbs where possible.

again apology for misunderstanding, Iā€™m not always very good communicating.

Mostly it will be STL for jewellery printing.

Yes, and this makes it very interesting and relevant to my [Still developing] workflow.

work flow sequence [as far as I found out by now]

  1. Making main parts in rhino [nurbs + subD] > then sending a very dens .obj to ZB for ornamentation and other work. > then rendering [Keyshot] and decimating dens mesh to .stl
    [I may open the .stl in rhino just for inspection but wonā€™t modify it in any way.

  2. But often, the ZB mesh will need to go back to rhino for gemstones setting and other precision needs [or simply to add a part that Iā€™m more comfortable making inside rhino].
    At time I can make all these parts separately and leave the ZB mesh unmodified [inside rhino] then take all back to ZB for Live-Boolean and finish the work in there.

  3. Yet, many times it would be [now already possible with simple geometry] very helpful to go back with the mesh to rhino nurbs.
    I tried to imagine a way this can be developed to work for very detailed parts as well. [wrote it as a replay to @theoutside. above in this thread]

thanks a lot
with best regards
Akash

Could the ā€œpackedā€ option be also be implemented for the regular Rebuild command?

(Also, why ā€œpackedā€, which to me, as a non-native English speaker sounds denser than the original, when it from the outside looks as if it should be ā€œoptimizedā€ or as the topic says ā€œcleanā€?)

I am not sure which conditions must be
satisfied for data conversion to occur correctly.

In my think Sub-D ā†’ ToNURBS very NICE.

Test Rabbit is Rhino Forum User up-load file. Thank you~

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