Do I understand correctly, that if I want to use TORTOISE for eddy correction before processing in 3D Slicer I need _DMC.nii output and my .bval and .bvec?
Yes that is correct.
You use the DMC.nii and the DMC.bvecs and DMC.bvals files.
However, bvecs/bvals files are not generated by default, only a Bmatrix (DMC.bmtxt) file is generated.
You can get the bvecs/bvals files can be obtained by running: