Full Version: A free subd to NURBS solution

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Patents might be a consideration?
- Brian

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Well, the T-Splines folks are not the only ones who created such technology.
The IntegrityWare folks created a subd to nurbs solution (patend pending) too.
ViaCAD has subd to nurbs tech also. And if you look at Github there are
also things called T-Splines.

Regards
Stefan

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I like Marco's idea of "Porting of the current Max's subDiv scripts, with a some degree of improvements, into the MoI's core tool set."

++ Plus ++

Stefan's idea of "Crease edges functionality."

Sell it as a MoI option. I'd get my wallet out for that! Then I could try designing more cars :)

Minor surface continuity issues are acceptably I think for software designed for quick & easy visualization. Professional designers are likely using something much more expensive than MoI.

Ed Ferguson

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My patent comment was merely cautionary.
- B

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PaQ
>>I really hope/pray Max will find the time and will to work on the surface simplification from his amazing subdiv script.
As I wrote earlier, I have a plans to implement this feature to Subdiv script. But at the moment it's difficult to do using current MoI Javascript API.
The current version of the Subdiv script saves an output data as a text STP file and then import it back to MoI. I can write a more complex stp export tool for stitched surfaces, but in my opinion it's waste of time.
Lets wait for a new js api functions in MoI v4.

Stefan
>>The person(s) who would take care of this problem *as a standalone product*, with crease edges functionality would IMHO win the jackpot, in the 3D Industry.
This script doesn't use any specific MoI functions. It can be easily ported to node.js project which can convert obj to stp. My script is free, so everyone can do it.
I'll think about this idea. But anyway it will be an opensource project.

Marco, Ed
>>I mean the porting of the current Max's subDiv scripts, with a some degree of improvements, into the Moi's core tool set.
Do you really need it as an internal tool? :) Everyone can use it right now for free.

Michael
Could you add this Zebra analysis to MoI? It will be very handy tool.

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Hi Marco,

> But...Do you think that the G2 continuity offered by the Moi's "Blend" tool is
> enough to deal with this kind of things ?

Well it's kind of the main point for sub-d in a CAD program to have the continuity automatically taken care of so you don't need to do blend style surface modeling.


> Or we (and Max) should need a more extended set of tools to generate this
> kind of "continuity" SubDiv ?

I don't know, I think it should be possible to have G2 continuity but maybe it needs a different approach using numerical analysis methods.


> So...this mean the end of our (or my) dream to see one day the "subDiv" script fused
> into the Moi's core engine ?

No not necessarily. But there will be plenty of work involved because sub-d modeling needs its own distinct workflow.

- Michael

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Hi Ed,

> Minor surface continuity issues are acceptably I think for software designed for quick & easy
> visualization. Professional designers are likely using something much more expensive than MoI.

This is true, but at the same time I am very frequently getting feedback from various kinds of professional designers who like to use MoI as well.

If it's possible for something to cover both the "quick & easy" _and_ "professional designer" cases that makes it more of a slam dunk to work on it.

- Michael

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Hi Max,

re:
> Could you add this Zebra analysis to MoI? It will be very handy tool.

It is something I want to add, it's a little finicky that you have to generate a very dense display mesh for it to work very well though. So it's not just a pure display mode addition it needs to involve mesh management in some way as well.

- Michael

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Hi Max.

Thank you very much for your detailed reply!

@You : "...Lets wait for a new js api functions in MoI v4..."

This is exactly what I'm waiting for :)

@You : "...Do you really need it as an internal tool? :) Everyone can use it right now for free..."

Oh yeah! It's amazing that all your scripts are free, especially SubDiv, but when I say "internal tool" I'm referring to something
that should leverage more heavily on some new V4 Api and that should be written in the same language Moi was written to.

Ciao! We'll catch up.

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Ciao Michael!

Thanks a lot for sharing your thoughts.

@You : "...I think it should be possible to have G2 continuity but maybe it needs a different approach using numerical analysis methods..."

Very interesting...but...I'm out of my league here :)

Anyway, I think that what you're talking here about is far beyond the things that we actually can do with the current Moi's Api.

Thanks again and have a nice day.

We'll catch up.

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P.S.

@You : "...I don't know, I think it should be possible to have G2 continuity but maybe it needs a different approach using numerical analysis methods..."

...unless you're talking about some sort of external standalone tool that should analyze for example the data of the same STEP file
that Max is currently using to perform his SubDiv calculation...

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// Maybe if you ask PaQ you will be provided with much more "heavy-duty" and reliable stuff :)

Hi Marco,

Simple example like the one you provide is better ... because I didn't realize so far that there was a continuity problem :/
In fact when dealing with super simple shape, I tend to add one or 2 level of catmull clark subdivision prior the conversion, the get a shape that looks closer to the one I have in Modo.
(It`s also a lame method to get 100% quads, whatever the topology was made of)

It seems to greatly reduce the continuity problem Michael describe (but not remove it completely) ... in the other hand surfaces around valence 5 vertex looks less `smooth`.

That having said, is there any existing tool around that gives a perfect result for this kind of conversion ?
Because from memory, T-spline (fusion 360) wasn't giving much better surfaces around poles either.

Thank you Max for the update, I obviously miss (or forgot) you previous message on the subject.

I get the idea of an external tool for this job, but in the other hand, Moi has already the best mesher, having the best sds to nurbs converter would add lot's of attraction !
... but maybe it required to much R&D for a single person.

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Hello PaQ!

@You : "...I tend to add one or 2 level of catmull clark...It seems to greatly reduce the continuity problem Michael describe..."

Thanks for the very useful tip!

@You : "...... but maybe it required to much R&D for a single person..."

I think it's nearly IMPOSSIBLE for a single person company.
Some sort of collaboration would be absolutely necessary, but, clearly, this would complicate the "trade matters".

Ciao!

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Hi guys,

I love reading about this subject. As part of my work involves creating toy models, I'm always searching for the perfect bridge between polygons and solids.

Max's solution for MoI is a great one, I am very happy it's here, and grateful that it's free, although I would happily pay extra for it.

The only drawbacks are that you need an all-quad and fairly low-polygon topology for the conversion to work out neatly. Better surface continuity for triangular polygons would be fantastic, and so would it be if the result could be optimized to as few patches as possible, based on curvature, so you could convert high-polygon models without a heavy, cluttered conversion result.

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@Metin : "...I would happily pay extra for it..."

+1
I too!

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@PaQ

Hi PaQ,

maybe someone can compare Marco's test model with this solution,
to see if there is a difference:

http://www.resurf3d.com/Objmesh2solid.htm

(The algorithm used in this software is based on the paper named Constructing C1 Surfaces of Arbitrary Topology using Biquadratic and Cicubic Splines written by Professor Jorg Peter.)

Regards
Stefan

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I googled over a dozen papers with J Peters name.
- B

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They are linking to this paper:

https://www.cise.ufl.edu/research/SurfLab/pre99-papers/9294.pdf

@Max

>I'll think about this idea

Thanks Max!

Regards
Stefan

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Hi guys,

The Resurf application is very old, and looking at the examples it doesn't do anything other than what Max's tools already do in MoI — converting each polygon of a low-res quad mesh into NURBS surfaces to form a solid.

Being able to do this in MoI would make me a veeery happy man:

Video 1:
https://www.youtube.com/watch?v=sPB-bHbKsJk

Video 2:
https://www.youtube.com/watch?v=4rDQCxGaLZ8

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Hi Metin,

sure it is very old, but does it produce the same little errors
Michael has shown with Zebra Analysis on Marco's model?

That was the question... ;-)

Best regards
Stefan

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