Weaverbird + 3d printing

Hello,

I have this very big problem while I want to make my model valid for rapid prototyping.

I work with the mesh to add textures: So I use wbstellate and wbframe. When I WBFrame it produces automatically without any obvious reason these errors:
Mesh has 744 faces with directions different from the mesh as a whole. Although this does not
necessarily mean that the mesh is bad, it can cause problems if you're doing mesh boolean operations with it.
Mesh has 588 pairs of faces that intersect each other. Although this does not
necessarily mean that the mesh is bad, it can cause problems if you're doing mesh boolean operations with it.

The guy from the 3d printing lab tells me he can't send it with faces intersecting to the 3d printer. So please who knows how i can wbframe without producing faces intersecting? cause its somehing I really dont get... I tried to do it manually: scale the boundary down and then booleandiff or trim etc but this produces intersecting faces as well...

Secondly, when I finally finish I need to offset the model cause its just an open mesh(srf) in order to get 2mm thickness so that it can be printed. OffsetMesh gives me a very bad result in terms of faces intersecting with each other. I tried WBthicken I tried this: http://www.grasshopper3d.com/forum/topics/offset-mesh-problems-with... nothing worked... I also tried to UnifySkin in ZBrush but couldnt reach the resolution of my model although I used the highest res... So now I am a bit desperate cause I really don't get it... I tried so hard and now in the final steps of preparing the model for printing I face really disapointing problems that cancel my whole work...

Thank you in advance

Rhino File is in here (40MB):

https://www.dropbox.com/s/x7g8h1liyyb1hhk/3d%20printing%20problem.3...

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Replies to This Discussion

Permalink Reply by martyn hogg on November 23, 2014 at 1:15pm

I can look at this with Magics software if you like... When I open the rhino file there are 3 objects... is it the object on the left that you want to print?

Or do you want to thicken the object in the centre?

Permalink Reply by martyn hogg on November 23, 2014 at 1:24pm

ok, something is weird with this file... when I save it the bounding box is HUGE!

dimensions = 1264482054665.26, 1259805953243.26, 661614493683.68 millimeters

Can you export the STL that you want to print? Magics can do something called shrink wrap which essentially does shrink wrap a surface onto the part which can then be processed for printing.

It seems like something might be corrupt because the object ends up being huge after export as an STL.

How come it is so big?

Permalink Reply by etsim on November 23, 2014 at 6:24pm

Oh sorry Martyn I just figured out that I have 4 objects in the file: the three that you described and a very very big one. You can delete the very very big one. The three small ones are the correct. Or you can use that file in which I have already deleted the big object: https://www.dropbox.com/s/8sj97sd5hgczt77/3dprinting%20problem2.3dm...

Permalink Reply by etsim on November 23, 2014 at 6:01pm

thank you very much martyn. The object to the left is the one I produced after offseting the mesh in Rhino, but it's full of faces intersecting each other etc, so you could work on this model or the cleanest solution would be to work on the model in the middle: It has 3 meshes the bubbles, the holes and the basic surface (mesh) of the bubbles. What should be offset is the holes and the basis of the bubbles by 2mm. After that there is a basis in the left model that should be put under the whole model so that it could stand on a table. That's only if you want to work in a cleaner way. Else the model on the left. Again, thank you very very much for your time.

Permalink Reply by martyn hogg on November 24, 2014 at 1:20pm

OK, I will have a look at this tonight... I've only just started using Magics software so I can't promise anything but it will be a good exercise!

Permalink Reply by martyn hogg on November 24, 2014 at 2:41pm

Well, this is what I did...

1. I took the middle object(s) and imported them into Magics.

2. I ran the Magics mesh fixing tools but I think it was a bit confused because it was a thin shell. It reported many inverted normals, holes, bad edges, intersecting mesh faces etc and couldn't really find a good fix for all the issues.

3. I imported the file again and tried the mesh offset to thicken it just by 1mm. It gets a reasonable result but still has errors where the offset creates intersecting mesh faces. The result looks better than the Rhino offset mesh and looks like it might actually stand on a table. It was a 53Mb STL file!

Unfortunately I do not have the Objet software on my laptop otherwise I would have tried to prep it for 3d printing but I have a feeling any slicing software will struggle to process this mesh and it would be quite an expensive risk to try and print it as is.

You might be able to take the thickened mesh and cut away at the problem areas, then manually tidy up the holes created but this would be a long, manual process.

I also tried a 2mm offset but this was less successful... I think what is really needed is a sort of intelligent offset whereby in areas where the offset creates intersecting mesh geometry, the offset is smoothed off in the intersecting areas. Sorry... no idea how you could do this.

Do you want me to upload the 53Mb STL somewhere? Can I upload it to your dropbox?