Is it necessary for a judge to have witnesses present during the session?

Primary text

The judge must have his witnesses present at his session to establish rights and formalize evidence and records. If the judge is one who rules based on his own knowledge, he may keep the witnesses near him or distant, summoning them only when needed to testify regarding his judgment. If the judge is one who does not rule based on his own knowledge, he must seat the witnesses close by so they may hear the litigants' discourse.