Netfabb Studio Tutorial - Part 1
The repair of this highly defect part involves the closing of holes, the removal of bad triangles, the repair of self-intersections, the removal of unnecessary shells and of double surfaces, the inverting of flipped triangles and the manual insertion of new triangles.
After the repair module is started, it can be seen instantly how defective the part is, as there are a great number of holes and inverted surfaces around the part. The statistics show that the part consists of 21 shells, has 393 holes, 6956 border edges and 3427 triangles with invalid orientation.
The repair is started by the simply functions "Stitch Triangles" and "Close Trivial Holes". This removes a lot of holes and unifies shells of the main body. The part now consists of only three shells. Also, the number of holes and border edges has decreased, while the number of triangles with invalid orientation has increased dramatically. Consequently, the function "Fix Flipped Triangles" is performed, which reduces the number of inverted triangles to 5600.
After conducting those simple, semi-automatic repair functions, the three shells shall be unified. First, the icon to select complete shells is clicked on and the single shells are selected to check, which sections of the part are complete shells. It seems that the top section, the main body and the base of the part form the three different shells.
As it seems unnecessary to keep an own shell at the base, and the bottom surface can be recreated by closing the main body shell, the lower (inverted) surface of the base shell is removed. This also opens the view to the interior of the main body. Thus, it is revealed, that there are inner side surfaces which are absolutely unnecessary for the production of the part and thus are removed.
In the middle of the part, double surfaces are visible, as there seem to be two parallel surfaces with different orientation. By choosing "Select Shells" and clicking on that surfaces, it can be found out to which shells they belong, and it turns out that they are part of the two different remaining shells. Thus, they should both be removed, as they are interior surfaces, and the shells should be connected where they come together at the edges of the double surface.
The option "Select Surfaces" is chosen and the selection tolerance is reduced to 5°, so that no triangles not belonging to the double surface are selected. Then, the surfaces can be selected and removed.
Behind the a section of the part is revealed which seems to consist of inverted triangles, as the blue outside is visible. The selection tolerance is increased again to select the curved surface. Then, the perspective is changed to see the top section of the part from the outside. It turns out that the selected inverted surface is the same as the one seen from the outside.
As not all inverted triangles are selected, the selection tolerance is increased further and the surface is selected from the outside. Looking on the part from the bottom again, it can be seen that all inverted triangles are selected. So, the function "Flip Selected Triangles" is executed by clicking on the icon in the toolbar.
Next, it is zoomed in to the the open border edges of the two shells where the double surfaces have been removed. The mode "Add Triangles" is activated and triangles are inserted at two opposite positions of the openings. Thus the shells are connected and the holes of the shell are only half the size. They can now be closed by right-clicking on the open edge and choosing "Close Hole" in the context menu. Also, the whole at the base of the part can now be closed again, as the interior looks fine.
To round off the repair all remaining holes are now closed by "Close All Holes". The part now consists of one shell without any holes. However, there is a high number of triangles with inverted orientation. This indicates that there may still be self-intersections within the shell.
The self-intersections are calculated and split off, which results in 25 shells. The main shell is selected, the selection is inverted and then, all selected triangles are removed. Thus, only the main shell remains.
Now, it has only 6 inverted triangles and two holes. These can be repaired with the functions "Fix Flipped Triangles" and "Close All Holes". Additionally, after the highlighting of errors showed degenerate faces, these bad triangles are deleted.
Finally, the part consists of one shell and does no longer have any damages.