Hi,

I wrote an evaluation of the two best 3D auto-retopology algorithms available today — 3D Coat's Autopo and ZBrush's ZRemesher. Read the article here:

http://www.metinseven.com/blog/Ag4W/3d-coat-vs-zbrush-auto-retopology-comparison

Although MoI isn't mentioned here, the retopology methods can be very useful for MoI 3D output as well.

Its great to see you mentioned Instant Meshes. While it does have some issues such as you mentioned, it is somewhat useful if one does not have 3DCoat or ZBrush. I've tried Blender, and usually end up with a mess as you have pictured.

Thanks Chris. I really like Instant Meshes, but the triangular dead-ends become visible artifacts when subdivided, and there are usually too many of those singularities to easily remove by hand.

Hi Metin,

if you like to check out an alternative to Instant Meshes you should take a look at
QuadriFlow. It is a CLI Tool and slower than Instant Meshes, but it produces meshes
with very litte singularities, compared to Instant Meshes.

https://github.com/hjwdzh/QuadriFlow

Regards
Stefan

Hi Metin,

i think this is most interesting when it comes to NURBS conversion, after auto-retopo...

I did a quick test and re-meshed the bunny with QuadriFlow and i think also with a higher
resolution and now after converting with Fusion360 i have much fewer patches than with
my old NURBS bunny and also more definition in the NURBS surface... :-)

I think i must do a better comparison again, with creating new bunny meshes and then
converting, to get a better picture, but i strongly believe it has to do with the fewer
singularities QuadriFlow produces.

The left bunny in my picture has 183 surfaces, while the right bunny has only 112! :-)



Regards
Stefan

Hi Stefan,

Many thanks for this very interesting tip, much appreciated! I hadn't heard of Quadriflow yet. It looks very promising.

You're a macOS user like I am, or am I mistaking? Do you know how to get this to work in the Terminal? Too bad there isn't a GUI (yet).

Michael, this could be an interesting algorithm to implement in Moi, don't you think?

It could be used for conversion of polygons to NURBS:

1: First offering the algorithm for retopology after polygon mesh import.
2: Then offering the option of polygon subdivision inside MoI.

And it would be great for mesh export topology as well.

Regards,

Metin

———————

visualization • pixel art • illustration • animation • 3D design — https://metinseven.nl

Does Quadriflow a "Line text command" program ?

Yes, looking at the page's instructions, it's a command line tool at the moment. I'm a reasonable Terminal noob on the Mac, so I'd love to see detailed instructions how I could install and use this.

Thanks!

Hi Metin and Pilou,

you need Developer Tools (C compiler and CMake) to compile the program and the you need also the
listed dependencies compiled, in order to use the program. And yes, Pilou it is a command line program.

Regards
Stefan

Hi Metin,

> Michael, this could be an interesting algorithm to implement in Moi, don't you think?

Well it's a polygon modeling operation that inputs polygons and output polygons, so it's probably not a great fit for MoI currently with MoI having no polygon modeling functionality in it.

- Michael

Hi all,
I like to add to this discussion on re-topology "Instant Field Aligned Meshes".....
"....The software converts geometry to uniform quad or triangle meshes, automatically following the curvature of the geometry and snapping edges to sharp features on the model."...etc
http://www.cgchannel.com/2015/11/download-free-auto-retopology-tool-instant-meshes/
http://igl.ethz.ch/projects/instant-meshes/
https://www.foundry.com/trends/design-visualisation/mitsuba-renderer-instant-meshes

regards
O.

Hi Metin,

to give you a better overview what to do... first install Apple's Developer Tools and it' command line utilities + CMake.
Once done install a package manager like MacPorts or Homebrew, to install the listed dependencies.

After that you simply follow the steps outlined on the Github page to download/compile and use the program.

Hope this helps.

Regards
Stefan

Hi Ken,

the link you give refers to Instant Meshes, which Mentin and i have mentioned.
Instant Meshes however creates more singularities in polygon meshes than
QuadriFlow, hence the reason why i posted this.

Regards
Stefan

Hi Stefan,

many thanks for clarifying this issue and apologies for being late !

best wishes
Ken

Thanks Stefan!

I'm afraid this is a bit too much hassle for me. I've always avoided going the Homebrew route. Back in the good ol' Amiga days I loved to dive deep into such things. Nowadays I've developed enough patience to wait for an easily usable implementation, without hacks and workarounds. :)

But I'm eager to use it as soon as there's a GUI or integration, maybe into Blender. I've started a topic at the Blender Artists forum about it:

https://blenderartists.org/t/new-quad-auto-retopology-algorithm/1124406

If you respond to the thread, it will be bumped up to the top of the thread list again. ;)

Hi Michael,

OK. I thought it could be an ideal algorithm to implement with regard to your plans for polygon to NURBS conversion inside MoI.

I was thinking of an import dialog offering to retopologize an imported polygon mesh using the algorithm, and add the option of subdivision like in the tools by Max, comparable to Stefan's bunny test.

On the other side, the algorithm could offer perfect quad-poly topology output inside the mesh export dialog, ready for subdivision in a polygon-based 3D editor.

Hi Metin, from a quick glance it looks like it's more oriented towards processing organic shapes. I'm not sure what would happen if you tried to feed it a CAD model with a mixture of large and small features in it.

- Michael

Good point, Michael.

Looking at the Siggraph paper...

http://stanford.edu/%7Ejingweih/papers/quadriflow/quadriflow.pdf

... the algorithm includes a sharp edge detection feature:

Hi Metin,

I understand. ;-) Maybe this topic should be posted at the 3D Coat forum, because
i think they have also Instant Meshes now included in the latest beta(s) of 3D Coat.

Maybe Andrew is faster than the Blender folks?!

Regards
Stefan