Hello! Could you please help me, is there a way to create a new segmentation and add asegment into it from simpleItk Image object (I mean the way through the python code)
You can read the SimpleITK image into a temporary labelmap volume node, import the labelmap volume node into the segmentation, then delete the labelmap volume node.
You can also use SimpleITK to create additional effects in Segment Editor. See an example of a SimpleITK-based segment editor effect here: https://github.com/lassoan/SlicerSegmentEditorExtraEffects/tree/master/SegmentEditorWatershed