HOW TO REPAIR A 3D SCAN FOR PRINTING

For these tutorials, I generated a free 123D Catch scan of an Ancient Mayan Musical Instrument from the Met!

common problems: holes, extra geometry, non-manifold faces

 goal:  to create a manifold, solid object for printing

DOWNLOAD PRINTABLE STL ON THINGIVERSE

Free Programs:
Meshmixer
Netfabb
Meshlab

Make sure to generate the highest quality mesh from 3D scanning software

Netfabb
initial repairs, making it solid
To show platform                                View       → Show platform

To rotate                                                 Click      → Pull corners when object is highlighted green

For a flat base                                       Cuts        → Drag Z and a line will appear along the model

→ Execute cut (turns into two objects)

→ Select unwanted one, right click → remove

Move to origin                                      Select     → Move to origin

Unwanted Pieces                                 Select     → Red Cross (repair), cracks will be highlighted

→ Select surfaces, click on unwanted material

→ remove unwanted triangles button (only big pieces)

Close holes                                                            → Click on automatic repair → default → execute

→ Export as STL Binary (another repair if needed)

Meshlab
smoothing and improving mesh (like a blanket on top)

 Smooth/Reconstruct                           Filter     → point set → surface reconstruction: poisson

→ Octree depth (start at 10)

                                                                 Layer     → Select Poisson mesh

→ Export selected layer as .obj

[vimeo vimeo.com/91575780]

Meshmixer
details, scale

                                                             Import   → .obj does better than .stl

For a flat base                                       Edit      → Plane Cut (shadow part will be discarded)

To repair holes                                     Edit      → Close Cracks

To make solid                                       Edit      → Make Solid

[vimeo vimeo.com/91576095]

Smooth/Highlight                                Tools     → brush (hold down shift to smooth, change size with cursor) → play with brush size, strength, etc.

[vimeo vimeo.com/91576096]

Scale                                                 Analysis    → Units/Scale

Replicator G
generate gcode

[vimeo vimeo.com/91577431]

Troubleshooting:

Netfabb Again
check for problems in the poisson file

For a flat base                                        Cuts       → Drag Z and a line will appear along the model

→ Check the triangulate button (will try to close hole)

→ Execute cut (turns into two objects) → Delete unwanted one

Run another repair in case

Blender
decimate (make the file smaller)

Click on Modifer (wrench)                                → decimate modifier. Anything above 300,000 faces too big.

→ type in a decimal ratio (i.e. .25) to get it around 100,000

→ if it looks good, hit apply, if not experiment

One more Netfabb repair
make sure it is printable

 

good resource: 3ders video tutorial