Operating System - Windows 10
Slicer 3D Version - 5.8.0
I am working with a dataset of a (cleaned, so no flesh) skull with the teeth in occlusion, so I have to separate the upper and lower jaws to get the morphological data I need.
I have done this by thresholding the entire skull and then manually separating the upper and lower jaws using the scissors tool, particularly in areas where the teeth and TMJ are in contact. This is being done in slice view with 3D visualization turned off.
Attempting to draw on a slice to add/remove voxels from a layer often takes 10-20 seconds for Slicer 3D to process each action, compared to near-instant in other CT programs (e.g., Amira/Avizo). The size of voxel area being selected does not matter, timing a selection with a slice cut depth of 0 mm (immediate slice only) as well as one set to “unlimited” both took around 15 seconds.
This has occurred with multiple datasets, one 3.19 gB, one 3.03 gB, and one only about 860 mB, ruling out corruption of the data. The physical RAM on my system is close to or greater than 10x the size of these datasets in all cases. Task Manager reports only 69% of total memory is in use. During an action this increases to ~80%, but the program does not appear to be hitting memory limits.
All other programs such as web browsers were not open at this time. Slicer is also updated to the most recent version. Other colleagues have reported similar observations that Slicer 3D is extremely slow when trying to segment their datasets, though the size and other parameters of these data were not provided.
The thresholding tool works is a relatively timely manner. It also takes about 15 seconds to threshold the entire dataset, despite the amount of data processed being much larger. While thresholding the amount of memory used in Task Manager will hit 95-98% of total available memory space. This suggests the issue may be a glitch with the Scissors tool specifically, rather than a limit of too little RAM.
Checking the forum other users appear to have reported near-identical issues in the past (example: Segmentation tools very slow for file above a few hundred Mb). I have tried several of the solutions seen in these threads (e.g., removing a Wacom tablet), but with no luck. I am passing this on as the issue appears to persist in the most recent stable release of Slicer 3D.