Anybody knows, is it any converter that can convert nurbs to obj with 4-sided polygons?
Michael, I think it's hard to make if MOI does not have this option?

Hi Andrei, I do not know of any NURBS mesher that will generate only quads output. It's a pretty difficult thing because it involves a much different meshing process than what MoI currently does, instead of focusing on refining surfaces along each of their own surface UV grid it would instead have to follow along trim boundaries and try to offset those trim boundaries from one another and deal with areas where the offsets are colliding into one another.

Your best bet for generating all quads output is to start with a regular exported mesh and take that into a program that has retopology functions. 3D Coat is a good program for doing retopology work, and there is also a program called topogun which is specialized in doing just retopology work.

- Michael

You can import a file OBJ inside ZBrush for have only Quagrangles ;)

Hi Pilou,

> You can import a file OBJ inside ZBrush for have only Quagrangles ;)

Is the retopology done automatically at import time itself or do you need to go to a retopology function to generate quads after you have done the initial regular polygon structure import?

- Michael

Thanx Michael for answer, I'll try 3d coat.
Pilou, I tried Z-remesher, It not alwas produce good result.

Michael, it do it after Import, with retopology function.

As soon as you import something in Zbrush all is transfomated in Quads!

About the new ZRemesher you can draw some curves for aeras who don't satisfy about retopology

yes you are right, it converts on import.

Hmm, no it not convert.. Just tested.. In Zbrush it shows like it's quads, but I then export it and open in C4D, and it still triangles.. You have to use Z-remesher to make retopology..

As Zbrush works only with quad in internal
seems you have a special button when you export from it !





You can of course use some tools before for have a better topology but normally not necessary by default

No it works with triangles too)

It's impossible to make re topology in one second... It have on second to import model) Just run Z-remesher and it will it takes minimum 30 sec..
Quad button was enabled. Just try yourself.
Use PolyF button to see retopology.

You see a triangle yes, but I am not sure there is not a double vertex for make a quad! ;)
Isolate a triangle and read the count of vertex!

3d coats 1 button retopology (well, you have to puch it 3 times) with no changes of default.



I know it's a simplified example, but they have the edge and loop tools for someone that knows what they want, and to work in more complex models.

Pilou,
I noticed when you export obj from MOI in triangle and quads, it first create triangled model, than merge triangles that can be merged with easy (using some algorithms) and make it in seconds (may be I'm wrong Michael know better)). The same thing can make Zbrush in seconds but still model will have triangles.. If it will be so easy Michael made the option export in quads)

Michael, just noticed that when I subdivide with smooth function model that was exported from moi with quads+triangles, it make all polygons quad (white).
And when I run simple subdivide it not creates quads (red). What is the trick)?

And it's peaty that this method can not be used to convert all to quads because it distort a bit geometry when smoothing. It very noticeable on sharp edges, on smooth surfaces works good.

I have taken info from Pixologic team :)
Seems I was wrong when you import inside Zbrush an OBJ file geometry is not changed, triangles who are not coplanar or not excess a minium angle (like in your example above) are not changed in quad
and stay real triangles with 3 vertices!

Hi Andrei,

> If it will be so easy Michael made the option export in quads)

Unfortunately as I mentioned previously there is a tremendous amount of work involved in doing that, it's a very different meshing process than what MoI's mesher currently does.


> Michael, just noticed that when I subdivide with smooth function model that was exported from
> moi with quads+triangles, it make all polygons quad (white).
> And when I run simple subdivide it not creates quads (red). What is the trick)?

I'm not all that familiar with ZBrush but I think when you do subdivide with "smooth" mode it does a catmull-clark subdivision, and one of the side effects from how catmull-clark subdivision works is that triangles are divided by their centroids and become quads.

Unfortunately just simply having "all quads" in just any form does not really do much good - in order to have a good sub-d cage you need not only quads but also for those quads to be arranged in a sub-d friendly topology as well.


> And it's peaty that this method can not be used to convert all to quads because it distort a bit geometry when smoothing.

It's because it's more just a side effect of quads being generated from the Catmull-Clark polygon subdivision. It's not the same kind of quadification as retpologizing gives you.

Since the "quads & triangles" output from MoI is not generally suitable for sub-d smoothing you generally shouldn't use the "smooth" modifier for doing the subdivision in ZBrush, so that it just does plain polygon decimation rather than catmull-clark subdivision.


- Michael

I used subdivide in cinema 4D, but I think it's the same as Zbrush use.
I just started this theme because I need sometimes to make low-poly model from MOI models.
First I think I can export with low amount of polygons and then high poly but this not works good.

But now I think I solve problem.
I export from moi High poly and the use Zbrush, Z-remesher to make low poly.

Michael may be you will give some suggestions how to make low poly from MOI model?

As I can see I'm only person here that use MOI not for Cad models)) But for games stuff and Art)))

Hi Andrei,

> Michael may be you will give some suggestions how to make low poly from MOI model?

As I mentioned before you generally would use retopologizing tools for that, just like you mentioned you did using Z-remesher.

There are various retopology toolsets out there, you can experiment with different ones to see if you find one that suits you. ZBrush has one, 3D Coat has a good set of tools, also Blender, Modo, Topogun...

Some people like to start with a low res model out from MoI but other people like to start with a high res model out - it kind of depends on what you're doing specifically and whether you're going to try to create stuff like normal maps.

If you're only doing geometry and not any map baking, then you might generate lower poly output from MoI to start with before doing retopology.

If all you need are static low poly assets, you can just export low polygons directly from MoI and those may work for you as-is without retopology.

Maybe if you gave some more specific information on exactly what you're trying to do with the low poly assets that might help other people give some more specific suggestions - just saying "I want to do low poly" is not really much information to go on, there are many different kinds of workflows for different purposes.

- Michael

Also I improved this method by selecting Devide large than - All. It produce more accurate cage for Z- remesher.

Michael sorry i'll tell more detail about what i need with low poly model, in my environment low poly means only one make model for game or animation)))
I need low poly for games first of all, to bake normal maps and other if needed from high poly and put it on low poly.