See attached testcase (DispTest1.fx). Calling FloatMap.setSample() should automatically cause any related nodes to be repainted, I would expect, but this is not the case. Originally I had intended that calling setSample() would mark any DisplacementMap effects as dirty (in theory you could have one FloatMap shared by many DisplacementMap effects), and would therefore cause any nodes attached to those DisplacementMap effect instances to be repainted. Apparently the implementation was never fully completed in this regard. This should be fixed since there is no other way to force a repaint other than to force an innocuous change on some other visual property.