Hi Eric, For processing scans in Meshlab, I align the scans and delete areas from individual scans that weren't captured well--usually the outer edges of each scan. You can remove these ugly areas before aligning as well--sometimes it helps to align and then remove ugly areas from individual scans. Save your edited scans along the way in case you mess up (save edited, aligned, etc.). You don't have to edit if you're happy with how your scans look--you can just align and proceed with the steps below.
Once you have a set of aligned scans that look good, make sure you "Freeze Current Matrix" of all layers--right-click on a layer to access this option and also save these. Right-click on a layer again and apply "Flatten Visible Layers"--this will merge all your layers into one (save as a new PLY). To convert this to a mesh, I like using Filters --> Remeshing, Simplification and Reconstruction --> Surface Reconstruction: Screened Poisson. You will have to play around with the Reconstruction depth to see what produces enough detail for you--I usually use 9 or 10. If Poisson doesn't work, check the "Pre-clean" box or apply "Remove unreferenced vertices" under the cleaning filter or you might also need to recompute normals under the Normals filter. Once you get a mesh, apply a cleaning step to remove any floaty bits that might have been produced--Filters --> Cleaning --> Remove Isolated Pieces (wrt Diameter). You will get a watertight mesh that you can export as a new PLY to use in SlicerMorph, R, etc. You shouldn't have to apply any smoothing or hole-filling after Poisson reconstruction, but you may want to decimate with Quadratic Edge Collapse if needed as mentioned in previous replies. There are videos describing a scan processing pipeline on Meshlab's youtube: https://www.youtube.com/user/MrPMeshLabTutorials that demonstrate these filters. If your scans were collected with the same settings, then your processing steps in Meshlab should produce consistent models. Save along the way! Sometimes it might be easier to align scans based on "regions" of your object rather than sticking to the scan families--that's what I like about processing scans in Meshlab! I hope this helps. Feel free to email me with questions. Terrie Simmons-Ehrhardt On Friday, August 28, 2020 at 8:27:25 PM UTC-4 [email protected] wrote: > Hello everyone, > > I'm just starting out in 3D GM and I'm really stuck when it comes to > figuring out a workflow for producing 3D surface meshes that are de-noised > without losing topological integrity, making them suitable for analysis. > > I've been using a NextEngine Ultra HD laser scanner for producing scans. > I've then been moving the scans into Meshlab to to do everything else, from > aligning and fusing to repairing and smoothing. I've come to view the > number of filters in Meshlab to be both a blessing and a curse. I've also > looked into MeshMixer, but everything seems to be black-boxed, and that > make me a little uneasy. > > I'm also confused as to the order of steps. Should I fuse my scans and > then clean and repair, or vice versa? What is the best way to de-noise? > Should I smooth or remesh? In what order should I be applying filters? > > I'm hoping that someone here might be able to suggest a workflow to guide > me through the process or direct me to some publications that can answer > all of my questions. Also feel free to suggest some other 3D mesh > applications that I'm likely not aware of. > > Any advice would be greatly appreciated. Thanks everyone! > > Best, > Eric > -- You received this message because you are subscribed to the Google Groups "Morphmet" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/morphmet2/f0a0caa6-145d-4342-8d9f-51fcadd3cd9fn%40googlegroups.com.
