ZBrush 4 looks like an amazing upgrade (free for all registered users)

GoZ http://www.zbrushcentral.com/zbc/showthread.php?t=71414

Spotlight and Lightbox http://www.zbrushcentral.com/zbc/showthread.php?t=071829
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here is an example showing what I would like to achieve (look @ the sofa not the girl)

so let say I have design a sofa in MoI and then I want to export to 3d-Coat or ZBrush to add some "life" to it, add stitches, Creases etc. the question is which one of the two make better use of exported geometry from MoI?


Image Courtesy of sdmolyne

Both can do that you want ;)
Say your have 2 crazzy products but one is 2.5 costless ;)
If you are a professionnal Zbrush is yet and will be indispensable
If you are a hobbyst 3DCoat is sufficient

Best is of course have both ;)

But If you have no money, Blender + Sketchup are the must ;)

Hi neo,

Well I can only talk about Zbrush here, and my reply will not please MoI users I suppose, but MoI is not the right tool for that kind of work, at least if you want to get this amazing result.

The workflow for that high quality model is to build the sofa in a poly modeler software, using subdivision surface technique. When the cage object is ready, you need to create super clean uv's for it, then export everything in Zbrush, adding the details, capture those details by computing a displacement map in zbrush, and finally apply this displacement map on your object, in a rendering software of you choice, using mico dislpacement technology.

All the details are added at rendertime (little memory footprint). So you can easily render 10.000.000 - 15.000.000 micro-polys for the sofa while the opengl viewport have to deal with only 5.000 polys.

MoI can generate nice mesh, but you can't apply subdision on it without destroy the model (remember, the best sculpting method is to import a low res poly model in zbrush, subdivide it, sculpt it, subdivide it, scuplt and so on ... this multi-res sculping method give you the best results ...) . A solution is to tesselate the model quite a lot at the export, using the 'divide larger than' option to have a regular meshing result, but then you are dealing with a big 'base' mesh allready ... it's not very handy to sculpt on it, uv's are a nightmare to deal with. And if you manage to get a nice end result in zbrush, but good luck to export and use that huge mesh in an other 3d package.

< but good luck to export and use that huge mesh in an other 3d package.
Now Zbrush has the best decimation of polygons file existing!
Decimation Master (more Centimation master as you win a factor 100 !
http://www.zbrushcentral.com/zbc/showthread.php?t=071265

I think what Paq is eluding to is that the model has to be >subdivision friendly< for it to get into ZBrush.

A lot of my Moi models could never make it into ZBrush (or 3D-Coat previously) to use the wonderful toolsets contained within.


Fortunately now, 3D-Coat has an excellent retopo toolset and the "import for pixel painting" function where you can get your mechanical models in without them becoming mushed.

Whether ZB4 will work with ngons better, I don't know but if your models don't look good after subdivision then ZBrush as it stands now, is not a tool that you'll be able to use much.
(Unless of course Michael can create that ever-elusive all quads exporter!)

-Will

Hi PaQ, just one thing to keep in mind is that not everyone uses ZBrush for exporting to a rendering program - some people want to generate STL data to produce a physical model.

> And if you manage to get a nice end result in zbrush, but good
> luck to export and use that huge mesh in an other 3d package.

When you're trying to create a physical model, you absolutely need to export the huge frozen mesh data directly to the CAM or STL software, because it does not know anything about sub-d or render-time only methods at all, it only knows how to deal with direct geometry.

So for this type of use, you just cannot rely on a render-dependent workflow like you were describing.

When using this physical-model based approach, you can get good results by using "Divide larger than" at export time from MoI to get a finely diced up base mesh, and make sure to use "Export: Quads & Triangles" as well, since ZBrush does not handle n-gons properly (it just converts them to triangles by connecting all points of the n-gon to a single centroid point, which give you a bad result if the n-gon is concave).

Using this method can definitely work with great results - I demonstrated it specifically in this previous post:
http://moi3d.com/forum/index.php?webtag=MOI&msg=804.26

Also another example from a user:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1045.1

The sword and shield in that last link were created in this exact manner, and as you can see it is a great result - small details such as the knurled handle and embossed bits of the shield were added in ZBrush on top of the base object that was created in MoI.

You can see his final physical model result here:
http://www.3d-miniatures.com/tiki-browse_image.php?galleryId=1&sort_mode=created_desc&imageId=56&scalesize=o


So I definitely don't agree that it is an automatically bad decision to use MoI and ZBrush in combination with one another, there are a couple of examples there that specifically show how it can be a good combination especially for the right kind of target output where a heavy raw geometry result is actually required (STL/physical model generation).

But if your primary goal is to generate a "render displacement friendly" type output, with lighter base geometry, I certainly agree that target will not work with output from MoI into ZBrush because the MoI generated mesh is not suitable for use as a sub-d hull. Just keep in mind that not everyone has that exact same goal, some people are using it for physical model generation and not rendering.

- Michael

Hi neo,

> here is an example showing what I would like to achieve

You mean you want to construct a sofa you can actually sit on in your living room?

Or do you mean you want to make a rendered image of a sofa?

Or do you mean you want to make a sofa figurine with an STL machine of a small sofa model?

Or do you want to cut a sofa object on a CNC?

Or do you want to make an long rendered animation with a sofa in it?


The methods you would use to get your result can be pretty different depending on which of these specific goals you actually have in mind - just saying you want to "achieve a sofa" is a bit too generic to really give specific advice.


> so let say I have design a sofa in MoI and then I want to export
> to 3d-Coat or ZBrush to add some "life" to it, add stitches,
> Creases etc. the question is which one of the two make better
> use of exported geometry from MoI?

Well, if your main goal is to produce a highly detailed rendering with an extremely high poly count, then you would probably want to look at not using MoI at all like PaQ mentioned and instead you would want to produce a Sub-d model + displacement map.

Basically if your target shape is completely covered in a lot of little tiny bumps and wrinkles, probably MoI is not really going to be the best tool for that kind of a job. You would want to look into a Sub-d modeler for that kind of a thing, they are focused on producing organic shapes like monster heads and things like that which have a lot of little tiny lumps and high frequency details in them.

I think your example there is more in the "lots of organic detail" type category (rather than more "mechanical base + some embossing"), so probably working from the beginning in one of those modelers that are focused much more entirely on that kind of shaping would be better for you here.

- Michael

Hi Will,

> (Unless of course Michael can create that ever-elusive all quads exporter!)

Well, one additional tricky thing is that even if I had that it would not necessarily be a universal solution.

When MoI generates a mesh, it creates the mesh vertices on your existing surfaces.

Even if the polygons were generated with an all-quad topology, if you then turned around and used those same quads as a sub-d hull and then did further subdivisions, your subdivided results are not going to follow the original NURBS surfaces directly, there would be a kind of additional "melting" or shrinking-down kind of modification happening.

That may be fine if you want a very melted kind of a thing, but I would not be surprised to see things like some bumps and undulations being formed that were not in the original NURBS model.

So it's just not at all certain that converting to an "all quad" polygon mesh would actually be completely equivalent to a seamless conversion to sub-d...

Of course it would certainly be useful in many situations though, I'm just not very confident it would be a totally magic conversion thing like it kind of sounds like you would expect.

- Michael

Hi neo, just a bit more information...

> the question is which one of the two make better use
> of exported geometry from MoI?

Check out a recent discussion on the comparision here:
http://www.3d-coat.com/forum/index.php?showtopic=2724

One thing that is pretty interesting about 3DCoat is its "voxel" mode, which works rather differently than a displacement map type method.

If I understand things correctly, when working in that voxel mode, it does not really rely on subdividing the base polygon geometry to add further details - instead basically the imported data will just "turn on" an initial set of voxels and then the imported geometry is not used anymore and you work with manipulating voxels only after that.

So when working in that new voxel mode in 3DCoat, there is probably not any advantage to having an initial sub-d model versus a MoI-generated model. In other words, that new mode of 3DCoat may be more generally friendly to MoI exported data.

When you are done manipulating things in the voxel mode, then it sounds like you convert it back into polygons by using the retopologizing tools.

That mode in 3DCoat is a pretty different way of working than ZBrush, and it may be an easier way to incorporate any kind of MoI model as the base object.

- Michael

Also a tutorial for going from MoI to 3D Coat to Cinema4D is available here:
http://www.3d-coat.com/forum/index.php?showtopic=2166

That's just for painting and not sculpting but it may be useful.

- Michael

Actually I'm surprised to see that all tris went into ZBrush that good! (I never saw that thread before!)

Certainly something to give a try!

Ultimately everything is a tri anyway it's just maintaining the wonderfully clean mesh from MoI upon import to other apps!

Maybe one day the 3D world will be all tsplines and we'll have the best of everything :-P

-Will

Hi Will,

> Actually I'm surprised to see that all tris went into ZBrush that good!

It seems that ZBrush is able to handle high density data itself quite well, just make sure to turn off n-gons at export from MoI, and if you subdivide a MoI model inside of ZBrush, turn off the "smooth" (sub-d) subdivision option.

Also make sure you export a dense initial mesh out of MoI as well, using the "Divide larger than" parameter to dice up any big polygons.


I think the main issue is you need to worry more about what you are going to be doing with this model after you are done in ZBrush... If you are trying to make a bunch of characters for an animation for example, it is going to kill your animation program if you have 10 million polygons for each character.

If you know that you want to have a light sub-d cage + displacement map result out of ZBrush, then you would not want to use a MoI model to go into ZBrush since you won't get that kind of a result out the other end.

But if you know that you want to have a dense geometry final result, then it can work fine. You'll kind of want to watch how much subdivision you do so it doesn't get too huge with this method though. But it is feasible to add embossing detail to a basic object while keeping things more like 100,000 to 300,000 polygons rather than in the millions.

- Michael

PaQ thanks for your reply, I'm aware of all that I was just hoping some kind of improvement have been done between Nurbs modelers and painting apps.
I just fund it counterproductive that I have to redraw a mesh with correct topology in top of the original is the worst part of the process in my opinion. So I wanted to know if anybody here use some different
approach.
Anyway within few lines you describes the hole process in a very informative way.

Could nPower's quad mesher be useful in situations like that?
http://www.npowersoftware.com/booleans/pboverview.htm

> (Unless of course Michael can create that ever-elusive all quads exporter!)

1st. workflow is to Save from Rhino/MoI as .stl. Then I open it with meshlab. I "unify duplicate vertices" and then save
it as an .obj. Then it can be sculpted Zbrush.
http://meshlab.sourceforge.net/

2nd. workflow http://alice.loria.fr/WIKI/index.php/Graphite/PGP

Both free but not a magic Bullet.

3rd. workflow COMING SOON

Will this on involves 3d-coat voxelsculpting>quadrangulated>converted to tsplines>converted to nurbs>SolidWorks>Modo. VOILA



>Maybe one day the 3D world will be all tsplines and we'll have the best of everything :-P

I have been dreaming about that day

Hi neo,

> Could nPower's quad mesher be useful in situations like that?

In theory...

But I actually have the code for that quad mesher included in the Solids++ geometry library that I use, and I tried hooking it up and found it to not be robust enough for general use.

If you look at the image in the link you posted a bit more closely you can see that particular example would be good for making a kind of pseudo-fillet along the hard edges, that part is fine.

But on the internal parts you can see that there are some irregular areas, some quads that are nearly shaped as triangles. This is not really a problem in planar areas like the case shown there, but if the surface is curved those kinds of topological irregularities would probably produce some bumps or undulations when they were used as a source sub-d cage.

It's pretty easy to get things like lumps in sub-d surfaces, here is a tutorial that may help to explain:
http://www.guerrillacg.org/home/3d-polygon-modeling/subdivision-topology-artifacts

It tends to take some experience and human intelligence to make good sub-d friendly topology choices, I'm not very confident that a completely automated tiling mechanism is going to be able to do the same job in all cases...

But certainly it would still be useful in certain circumstances - if your main goal would be to round off sharp edges that part would probably work well with that style of quadifying, since the topology is good exactly along the original edges - it is where things collide internally that make problems.

But basically, I would say to not expect a magic silver bullet comprehensive "works everywhere" solution from something like that.

- Michael

Hi neo,

> 1st. workflow <...>
> 2nd. workflow <...>
> 3rd. workflow COMING SOON

What is it that you're trying to accomplish with all these things?

If you want to create sub-d output as a final result, most likely your best bet will be to create your model as a sub-d model, using sub-d tools from the beginning rather than using a different toolset and trying to somehow convert it later on.

Otherwise, one route that looks pretty promising for conversion is the retopo tools in 3DCoat. But if you don't have enough time to invest in doing that then you probably won't really have enough time to do what you want overall really.

It is just not very likely that you will find an automatic push button solutions, to make a high quality model you do generally need to invest some time and gain some skills to make such things come out well.

- Michael

Perhaps if some spoke from real experience with the latest version of 3D Coat, some of these various comments would be seen as superflous.

A flow between MoI, 3D Coat, and, as for me, Carrara 7 Pro, seems very logical.

Certainly, for ease of use/cost/ within my needs, far better than the Z alternative!

Brian

>What is it that you're trying to accomplish with all these things?

Are You Being Sarcastic? If not here we go.

1st. workflow (Graphite) & 2nd. workflow (meshlab) was more like a tip to whom wants to convert tris to quads.
I do build physical prototypes which then I scan after that I refine the mesh with Graphite or meshlab for further use in ZBrush, Modo etc....(depends the nature of the project).

3rd workflow. Well better show these images by yolk than writing an essay. you can see most of the workflow I was describing earlier.


quadrangulate voxel sculpting.


Converted to Nurbs with tsplines


imported into solidworks, shelled (wall thickness) and groove added.
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Now for "render friendly" output, Modo 401 will have a solidWorks importer. (but I'm skeptical about the mesh quality. I imagine the mesh that is saved with the SW file for screen display will be what 401 Imports. But this is still a nasty STL like mesh.)...time will show.

"If you know that you want to have a light sub-d cage + displacement map result out of ZBrush, then you would not want to use a MoI model to go into ZBrush since you won't get that kind of a result out the other end.

But if you know that you want to have a dense geometry final result, then it can work fine. You'll kind of want to watch how much subdivision you do so it doesn't get too huge with this method though. But it is feasible to add embossing detail to a basic object while keeping things more like 100,000 to 300,000 polygons rather than in the millions."


Hi Michael, I guess this is rhetorical (until I try it for myself), but couldn't I use the hi-poly export from MoI into ZBrush generate the normal/displacement maps and then using a seperate, clean MoI ngon export use that as the low poly base object and just load up the paint & displace maps?

Or would I need the low-poly model in there as well as a part of the displacement process? (I believe that's (unfortunately) the case since I think it needs the level 0 base to refer to for the map generation...)

I also don't now if you can use normal/displace maps from a all tris model onto an ngon topology either.


Just asking, being that I've never attempted to generate normal/displacement maps from my models yet...



Using hi / lo MoI exports would be fine - my probs have always been just getting the models into ZBrush in the first place!

-Will

PS - Thinking a bit further - the normals/displacements would come from the initial tris input vs the displacements and additions I add to the model within ZBrush.

The question then is can I project those maps back onto an ngon version of the model??