trying to repair a model for 3d printing

[dthomas6184]

This is the wrong forum, but there is no forum for Netfabb!

I'm trying to get a model of a helmet ready to print but it wont let me make the holes for my head or the visor without throwing an error, and when I go to repair it it just fills in everything

the helmet is made up of 3 pieces, i've tried editing them individually then joining them and joining them, creating a shell with 5mm thickness then editing them but the end result is still the same.

[davebYYPCU]

Sounds like Netfabb is telling you the model has errors.

To fix them we need to see what you have done, with file, pictures or a screencast, presuming the model is from Fusion in the first place.

[dthomas6184]

The model wasn't created in fusion, it's an STL file downloaded from destinystlgenerator.com. I will upload a copy of both the original file and the one I am working on when I get to my desk.

[dthomas6184]

attached is the original file and 1 of my attempts at trying to make a printable shell.

I was trying to take the 3 pieces that made up the main part of the helmet and combine the together then turn the whole thing into a shell 5mm thick. 

when I open the file in Netfabb i'm given the option to keep all parts separate and to repair the ones that need it, now after I repair the pieces they all become solid. 

[steffen_anders_adsk · Accepted solution]

Hi,

Netfabb's default repair consists of scipts, batches of repair actions. But they are examples which, while they do catch most of the issues, may hurt your individual model. As such, you may not need all of the actions included. You should examine your models what the actual problems are and then apply the actions appropriate.

Your model consists of lots of individual shells, partly grouped, that are actually just open surfaces, not properly closed shells. Also, they are intersecting with each other. You need a properly continuous surface for further print preparation steps. Also, only two triangles can meet at a border. It is not allowed that three or more triangles share the same edge, or that their edges "touch". (A cross-section of three triangles, for example, would look like a T-junction. Not allowed.) An example for that would be the inner head contour surface that ends at some point and joins the outer skin in a seam:

You would need to manufacture that head contour somehow separately. In fact, because the model is supposed to have an inside, you might want to see to finding a proper contour, like the mesh of a head, to use as the inside, rather than using the hollowing function. Or, perform the "hollowing" by finishing the whole model into a solid piece, and then adding an inner offset during slicing.

To get you started, I'd suggest you do the following:

1. Split part into shells.
2. Pick and mix the shells you want to keep, and discard the ones you don't. You may also want to sort them into groups to organize them and toggle visibility of "shells to keep" and "shells to disregard", rather than actually deleting the unwanted ones.
3. Merge all wanted shells into a new part.
4. Use the Repair, Split off Self-Intersections, to split off any and all self-intersections. Apply this repair without any further repair steps into a new part.
5. Repeat step 1 and 2.
6. Use Repair to manually delete any further, unneeded triangles until all of your triangles only ever meet or share with exactly one other triangle at their edge.
7. Use Repair, Stitch Triangles to close the seams.

Make use of the X, Y, and Z clipping planes (no cutting, just toggling visibility) to get a better insight.

Also, because your model is symmetrical, don't forget you can split the model in two sides, edit one half, discard the other, and then duplicate, mirror, and merge to save on editing time. 😉

Here's what your model could look like at an intermediate step:

Best of success!

Steffen

[dthomas6184]

worked like a charm! thanks