hi Huizhang –
All of the command-line programs in the BrainSuite bin dir that write surface files should save them as .stl files if you use the .stl extension for the output file. The caveat to this is that stl files don’t carry enough information for the BrainSuite pipelines to use them as inputs, so effectively you would need to run a step twice to get a .dfs version and a .stl version. We don’t have a file converter program included with the software, but I will probably add one for the next release.
You could try this with dfs if you have a mask file. Below is an example on my Mac. You can see it generates a .stl file.
shattuck:~>/Applications/BrainSuite21a/bin/dfs -i /Applications/BrainSuite21a/svreg/BCI-DNI_brain_atlas/BCI-DNI_brain.cortex.dewisp.mask.nii.gz -o brain.stl
wrote surface file brain.stl
shattuck:~>head brain.stl
solid brain.stl
facet normal 0 0 0
outer loop
vertex 46.5981 106.954 80.565
vertex 46.1262 106.945 80.6693
vertex 46.4666 106.725 80.639
endloop
endfacet
facet normal 0 0 0
outer loop
thanks,
David