Z-Brush 3.1 to Rhino V4 to Prototyping

[Hurricks]

Done a few searches to date on this subject and can’t quite find the answer I’m looking for…

My questions are, in context with the consequent user information:

1. If I make a model using a series of subtools how do I then make the mesh one single solid mesh in Z-Brush?

2. If I use Mesh Insert to create a single tool from a series of sub tools, what is the best method for retopologising the resultant mesh to form a new tool?

Those are my main concerns at the moment. I’ll give you some background on what I’ve been doing… it should make the questions meaning more relevant….

I’m using z-brush 3.1 to create items such as shoes, sports equipment, fully clothed figures etc. Normally I will create these using a series of sub tools. When happy I use the insert mesh function to create one single sub tool.

However, when I export to Rhino V4 using the .obj export option, I find that the MESH created is joined, but all the subtools are in fact still present (each sub tool is solid, but remain as individual parts).

see pictures:

However, as you can also see, I’ve developed some undesirable wrinkles in my surface. These aren’t present on the original model. I’ve already resolved some of these errors using the smooth brush. However the smooth brush is pretty useless around the studs of the boot as it unrealistically deforms them.

Anyone got any ideas how to achieve what I’m looking for? Am I on the right track or down a dark ally on this one? Please help and thanks for reading.

Hurricks

PS I’ve only been using Z-Brush since Nov 08, so please forgive me if I’ve missing the blatantly obvious on this one!

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[Totyo]

Hi Hurricks,

In fact, you are working in ZBrush like in a NURBS software, but as you can guess, you can’t do such boolean operations in ZBrush like you can do them in Rhino. The mesh insert just do… a mesh insert like welding two intersecting objects and it doesn’t remove the non visible parts.

Thats’ why you see all the Subtools as different objects in Rhino.

To solve the problem, you have the solution of the retopology but on some specific topology, you can have a lot of troubles because of the projection. Did you try to change the projection settings (decreasing the range, etc.)

Another solution may be to use the ZProject brush and/or the Projection feature of the Subtool. It can project an information of a Subtool to another, meaning that you deform one object, based on another. it doesn’t create a new topology, it just move it.

At the end, what do you need? A single mesh or a mesh with several accessories/parts?

Can you post a screen capture of your object before trying to do the retopology, to see it before your operations?

Edit: the only way to avoid too much polygons before exporting is to reduce your subdivision levels, no other way…

[gabo1991]

Hi Hurrick

On top of what Totyo (thanks Thomas) said I would use Subtool Master to merge all the subtools. It will be faster then mesh insert but will still retain the subtools information. Download it here

http://www.zbrushcentral.com/zbc/showthread.php?t=66035

I would also use the morph brush in conjunction with the project brush. Fabricio Torres has a good thread of a trick he did doing eactly what you want. Here is the link:

http://www.zbrushcentral.com/zbc/showthread.php?t=63228&page=2&pp=15

It’s on page 2.

Let me know if this helps along with Thomas’s information.

Paul

[Hurricks]

Thanks Paul & Thomas, much appreciated! I’ve just read your replies and will look into these further in a minute.

I did manage to figure out a workflow… whether its the best is another matter, hense I’ll have a read of the suggest thread & download Subtool Master in a little while.

Here is my workflow:
1.

Imported back into Rhino. Unified Mesh Normals… which wasn’t needed as the surface was already unified. RESULT! Lost a bit of detail, but in essence it worked.

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[gabo1991]

So you rebuilt the topology on the unified skin to make it happen?

Paul

[Hurricks]

Hi Paul,

Yes, put simply this is what I did.

I’ve downloaded subtool master - tried it on another model I’m working on and am impressed. Saved a bit of time and made the process pretty idiot proof, which is great.

I’ve also read the thread you gave me. Very useful tip in there about storing morph targets. I’m part way through testing the tip on one of my other projects i’m working on. so can’t fully comment at the mo. Probably wont be able to give you feedback on this until Tuesday when back in the office.

[gabo1991]

Hi Hurricks

No worries at all. please let me know how it goes.

Paul

[Hurricks]

Hi Paul,

Got no screen grabs to show you today, but I didn’t have much joy with the morph targets. I need to do some more reading on the subject, as I don’t think I totally understand the process at the mo. So not sure what I need to ask you specifically…

Due to time I resorted back to the technique described in my previous posting. Got a half decent mesh from it… had a small amount of spiking on the mesh, but I cleaned this up to a satisfactory level with the smooth brush. Exported the mesh to Rhino & all mesh normals were perfect.

I’d like to get the morph thing sussed though. I’ll probably come back to you again when I know what questions I need to ask.

Cheers,

Hurricks

[gabo1991]

ok. If it is easier for you we can always do a GOTOMEETING so I can see your screen or vise versa. I can also take control of your keyboard and mouse. Let me know.

Paul

[system]

Howdy,

I think I can give you a definitive answer on this as I go zbrush to RP using multiple subtools all the time.

From what I can see of your models it doesn’t look like this is giving you a very nice model compared to what you would normally have.

I’m not really sure why the RP bureau are giving you such beef about it, but meh.

Anyway, export your obj’s to Rhino and save as STLs. Rhino’s mesh editing is pants in my opinion, even the plug ins I find pretty much useless.

So, now this bit you might not like. You need to open your mesh in a dedicated mesh editor like Materialise Magics or Raindrop geomagic and you will then very quickly and easily be able to fill any holes in your meshes and boolean them together. This only takes a matter of a few minutes, so i dont really understand what the RP bureas problem is. It sounds like they are either workshy or just looking for any reason to screw you out of more money.

I think both Geomagic and Magics do trial versions of the software, and there might even be a free or cheaper alternative out there somewhere. You need to be looking for Point cloud interpretatio software or reverse engineering software i think.

[Hurricks]

Hi Jakakadave,

Great tips in theory. Magic’s is totally out of the question at £4,680 and Magic’s Lite at £1,650 would only be considered it we bought our own RP machine… Maybe happen one day….

In the meantime thanks for the tip on raindrop geomagics…. I’ll look into this as I have not heard of it before. Do you have any idea on cost?

In the meantime I’ll have to go down the re-top route as this is the only way I’ve found that I can produce a simple enough mesh to allow me to work further in Rhino to add engineered and toleranced portions of the product. Unless I’ve missed this feature somewhere in Z-Brush!?!?

[Hurricks]

wow - geomagics could be a touch expensive! lol $19,000 for the suit.

[system]

Well, it seems like a lot of work you are putting in to get something which isn’t quite as nice as you’d really want.

There must be a cheap/free program out there somewhere which can simply fill holes in an stl mesh, fix normals and do boolean operations. Get your google on, i just mentioned the two programs i know of which would solve your problem.

Following a quick google I’ve found:

http://www.deskartes.com/ - one called 3D data expert $1195

One called simply STL editor - not sure if it does boolean operations but it does does fill holes, refine and decimate meshes etc.

I’m sure if you applied yourself to a bit of searching you would find a solution. I think the search terms you’ll need are STL editor, STL boolean and stuff like that.

How much extra are the RP bureau asking for on average?

Are you providing them with STLs from Rhino?

At least if you know how easy it is to do what they are whingeing about, as they’ll almost certainly be using magics.

[Revanto]

I’m having a big problem with this sort of thing myself because it is a big part of my workflow. I don’t know why Zbrush doesn’t have a decent boolean function even with some sort of retoplogy assistance so that booleans can avoid those nasty triangulated areas you sometimes get.

Anyway, Whenever you do stuff like this it is VERY important that all your mesh parts are enclosed IE no holes. You also need a program that does booleans.

I may have a helpful little way you could try that might give you some workable.

• First, you need to download a free program called ‘Meshlab’.

• In Zbrush, export out all the hi res pieces as one as an OBJ.

• Load the mesh into Meshlab and go to filter > select > self intersecting faces.

• delect these polygons and save out the object as ‘mesh01’ or something

• reload the original mesh into meshlab and select the self intersecting faces again BUT this time invert the selection before deleting the polygons.

• save this mesh out as ‘mesh02’.

• In you native 3d program, load up ‘mesh01’ (this will be the mesh with the ‘seams’ removed). You now need to manually remove all of the 'hidden polygons IE the ones you can usually see if the mesh was whole. This can be tricky depending on how co-planar bit of the mesh were.

• You can now load up mesh02 and merge the points from mesh01.

You can now use this as better reference for when you ‘project all’ or retopologise. Again, it may not be perfect because of co-planar polygons but it should be cleaner than the original mesh.

Oh, I forgot to mention that Meshlab can fill any holes you have in your mesh. It’s in the filter menu somewhere. It can also reduce the number of polygons. I tried converting OBJ to STL once but the meshes came out ugly so I would avoid that function.

It’s not much but I hope it’s helpful.

Cheers,
Revanto

[Hurricks]

Hello again,

Sorry it’s taken so long to get back to you. Been a manic week! Been doing a bit more research on the Rhino end. Sounds like there are some great developments on the way, which should help!

Although this doesn’t totally resolve the problem I have found and downloaded a plug-in for Rhino called “MeshRepair”, this is saving me a fair bit of time as it automatically sorts out all the minor stuff at a touch of a button. Still gotta fix odd bits, but it seems to save a bit of work… which is all good.

I approached my last Z-Brush build slightly differently too. Tried to construct in the least number of sub-tools possible and made sure I maximised the thickness & overlap of each solid part. I’m intending to manufacture in Polyresin so chunky-ish parts are no bad thing as it reduces returns from breakages and makes it easier for it to be produced quickly in batch production.

The Boolean function in Rhino did stand-up to this model well, so didn’t have to re-top and didn’t loose any detail this time. I dare say, until Rhino’s Boolean stability improves I’ll have to resort to a number of different techniques depending on the nature of the part.

[Revanto]

OK, I’ve been loking around for a freeware program or plugin which can do mass booleans. Anyway, there is a programs called 3Dcoat (a commercial product, though) which may be able to do what I have been dreaming about. I don’t actually own the program because my cheapo system can’t run the program (never buy stupid ex-corporate flat top computers!!!) but I have seen a function which allows you to create a decent unified version of your mesh pieces. Once you have a unified/merged version, you can export it out for printing or use it to retopologise a mesh onto it.

Once I get a decent computer, I will get this program to help me with my design work.

Hope this can help you out with any futureprototyping pieces you may have.

Cheers,
Revanto

[Crusoe_the_Painter]

Depending on your prototyping provider, you may not even need to boolean all the meshes. Most can handle this.