stl files, 3d printing with Blender models

I modeled some jewels in Blender to print it with 3d printer at a jewel designer company. I give the files in stl format, but we have problems. The printer software says: the mesh is not closed. Of course, the mesh closed.

Have somebody any experience with this? Maybe the Blender stl exporter has problems?

Hi Endi.

I had that issue few times as well. I do not know what happens but obviously during the export something bad can happen to normal orientations.

Can you send me the blend file? I can open them with my CAD programs and send you maybe a better STL file. I can also test it on the zCorp printer we have here.

Which printer are they using? I assume a wax printer?!

Oh, this sounds like it has potential for Blender movie merchandising. It’d be sweet if I could take a model from XTIN project and, print off a toy or plastic model, and mail it to a customer.

Thank you for the help!

I don’t know the type of the printer, I have no direct contact to the printer company. :frowning:
Yes it is a wax printer. I have a friend who is a goldsmith (hm I don’t know the good word, so she make jewels :)). I want to help her by making her designs in 3d. I made 5 pieces, they can’t print no one… The printer program sometimes say: this is not closed mesh and sometimes shows very bad result on the print preview.
We can’t testing many because we have no money. :slight_smile: Hopefully we have print preview…

Sorry for my bad english. I will send you email!

I use MeshLab to check my STL files for issues like these… maybe it can help you to track down the problem.

I downloaded MeshLab and trying! Thank you!!!

I found this:
He uses Blender but I dont understand for what? :slight_smile:

I have read some articles on the net. Everybody talking about a software called Catalyst, that is the 3d printing software. It can check the stl files and can make print previews. Sot it can use without printer hardware… But I dont found a free or trial version on the net. Can somebody help me?
I have tried MeshLabs, but not help…

Hm! I have found this program: Quick 3d professional

It can load Blender stl and shows an error: maybe the normals are wrong. When I use “generate normals” function, model rendered correct!
Maybe I will give this files to printing!

hm, here I found an old stl exporter for Blender:

it can export good result to quick3d…

Blender sometimes produces bad normals! maybe that was the problem!
I had that in one of my last models as well.

I know this thread is rather old, but I thought before opening a new one I might as well just use this one, because I have the same kind of problem.

I am modelling a piece of jewellery which my girlfriend wants to print with a wax printer (she’s a gold smith).

I already know that I have to check if the model is manifold (have done that, and it is).

But there are still two specific questions left, which I want to ask before I give her the .stl-file:

  1. The mesh has a ring shape. I am sure that the printer (I guess not even the .stl-format itself) knows what a subsurf modifier, an edge split modifier or Blender’s “smoothing” is. So how can I get a really smooth ring in the end?

Do I just need to make it with enough vertices, so you can’t see the edges anymore? And if so? Does anybody have an idea how many vertices I would need for a ring with a 9 mm radius?

2.) How do the blender units translate into the printer’s units? I have modelled the ring using 1 blender unit = 1 mm. Do they have to set that in the printer software? Or is there a certain value? Or how else does it work?

I would be really happy, if somebody could help me with that.

Thanks a lot!


WOW! I just found this thread today while doing deep search on STL files (I am about to do my first 3D print) and then it pops to the top of the heap! Weird.
Please…can anyone answer these two questions posed above? I am wondering the same thing.

  1. apply the subsurf modifier before exporting
  2. do not use edgesplit modifier, mesh must be continous
  3. I use 0.3mm resolution on the jewels that I made (i think this is the minimum, better to use smaller)
    4 units: I send the file to the 3dprint company and I ask: is it x mm? :slight_smile: they say no, then I send another one with correct size

Hi endi!

Thanks for your quick answer.

Not to use the edgesplit modifier makes sense, I guess.
The subsurf modifier was actually just an example, but I am afraid I cannot use it with my mesh, because I have some sharp edges that I want to keep. If it helps, the mesh looks like this:

So I am still not sure how to get this smooth… You say you use the subsurf modifier and then the printer recognizes this? Or do you apply it before?

And what do you mean you use a 0.3 mm resolution? Do you mean in your modelling 1 blender unit = 0.3 mm?

Thank you for helping me!


why not add subsurf, crease the mesh well, then apply subsurf, then export?


you mesh it so fine that the print will not show faces.

In Rhino for example you set the mesh resolution to a point were it is fine enough.
the printing software will interpolate afterwards anyway again.


Hi Claas!

Thank you, that is exactly the news I wanted to hear! :yes:

Does anybody know exactly how the units translate? Because tomorrow is the last day before the winter break in the goldsmithing school with the printer, so I cannot really do it with the trial and error method that endi recommended (I can of course always do it after winter break, but it would be much better to do it tomorrow).

All the information I can give you (because that’s all the information I have):

The school uses Rhino. But I don’t know if they just use this for modelling or if this is also the program that directly communicates with the printer (not sure, if is able to do that).

Can anybody guess how it works and how the units translate?

Thank you for your help!


When I make the jewels I use Blender units. So 1 Blender unit maybe 1 cm. I send it and they says: this is 1mm or 1m? I dont know, but I know the only thing I do: scaling up or down the model by 10.


when you work in blender you can use blender units as a measurement system.

lets say a cube is 1 cm,cm,cm.

when you import it into a cad program you can say that this unit is cm and it should fit.
in addition you can also add just a guide line which is one cm.
in rhino this line could be scaled to one cm and thus also scales the complete stl file.


rhino stl the NURBS model for the printer but i do not think they feed the printer with.
we dont.

rhino is crap in many areas. we need to fix meshes in magics first because rhino the great CAD program often meshes bad, builds in holes by forgetting faces !!!