do a "help remeshsurf" see the possible options. For simplicity, you can set opt as a scalar, which will be the desired maximum element diameter of the resulting mesh; in that case, the grid-size will be set to opt/4 automatically.
Please do a meshresample first to reduce the mesh density and then do a remeshsurf; this can save a lot of memory for you.
By the way, do you have to keep the original surface more than 50%? FreeSurfer produces very dense surface mesh, for me, I usually keep only 5~10% of the elements. If you have a very dense surface mesh, tetgen will take a long time to make tetrahedral mesh.
You can also try MeshLab to manually select and correct these bad elements in the original mesh, but generally speaking, this is pretty difficult. I've chatted with the FreeSurfer developers in our building, but at this point, there is nothing we can do about it.
this the most frequently encountered error with iso2mesh (or tetgen). It is very likely that your original mesh contains self-intersecting elements, and mesh simplification (decimation) usually won't fix it (If you are using FreeSurfer, the pial surface it produced usually have this type of issue).
There is a work-around, but you might have to play with the options to get it to work. Please look into the sample script sample/demo_remesh_surface.m. It calls a function named remeshsurf in the toolbox. What this function does is to first convert a closed surface into a binary image, and then re-extract a surface from the volume, and the extraction script guarantees that the produced mesh is self-intersection free.
If your mesh is complex, you may have to use a large volume to re-voxelize your surface. Give it a try and let me know if it works.
Error: Invalid PLC.
Two subfaces (17561, 18027, 83603) and (83474, 83572, 18027) are found intersecting each other. Hint: Use -d switch to find all intersecting facets.volume mesh generation is complete
I am not sure the reason for this message and also if there is any potential work around it.