I am looking for an indicator or code for TradeStation or Multicharts that can plot the possible high and low for the current range bar (in Tradestation it is called momentum bar).
Wonder if anyone could help.

I can offer you an indicator for NT..
I know that does not help you but maybe it will help someone else looking for the same thing in Ninja format

How about this:

 

Code

{ plot the projected high and low for a range bar } Vars: BAplotLoop(maxbarsforward), k(0), projHigh(0), projLow(0); if bartype = 12 then begin // plot only if this is a range bar If LastBarOnChart then begin projHigh = low + (h[1]-l[1]); projLow = high - (h[1]-l[1]); for k = 0 to BAplotLoop begin Plot1[-k](projHigh, "High"); Plot2[-k](projLow, "Low"); end; noplot(1); noplot(2); end; end;

Regards,
-C

Thanks a lot, for your code. This has partially addressed to my question. As the price moving within the current bar (range), I would expect the possible high close and low close will change at the same time, before the current bar close. Could you help to let me know how to modify your code for it?

search for "scalper's high low" by TUMS

or

Scalper's HL Bracket by TAMS

Sorry, I was wrong. The high low lines do change during the current bar when price moves.
Thanks again.