This indicator is the Heiken Ashi Smoothed v1.1, updated to work with NinjaTrader 7.
It uses "NinjaTrader 7"-specific features, so cannot be used in any earlier version of NinjaTrader.

//#######################################################################
// v 1.3a modified by Osikani, April 7, 2012
//Summary of changes
//
// 1. Specially modified to be able to show underlying price bars. Posted
// to NinjaTrader Forum only. Requested by Forum user, dcassidy.
// 2. Separated enum into indicator specific namespace, so as not to
// pollute the global namespace.
// 3. Corrected HeikenAshi_High and HeikenAshi_Low to correctly account
// for the current bar HeikenAshi_Open.
//
//#######################################################################
// v 1.3 modified by Osikani, July 7, 2010
//Summary of changes
//
// 1. Moved declarations of enum variables outside the class.
// 2. Redefined default colors for Heiken-Ashi candles.
// 3. Added optional alerts and logging for when Heiken-Ashi bars change colors.
// (not implemented in this version. May be available in the commercial version)
// 4. User can define colors for the Heiken-Ashi candles independently of
// the chart's candle colors.
// 5. User can independently specify the color of Heiken-Ashi shadows.
// 6. Added line to show last price of equity.
//
//#######################################################################
// v 1.21 modified by Osikani, June 15, 2010
//Summary of changes
//
// 1. Modifed how the Heiken-Ashi bars are drawn, and how to clear the
// price bars. NT7 added a separate Pen for drawing the candle outline,
// so we needed to modify the second pen too.
//
// Also drawobjects z-order is not being strictly obeyed, so the wicks
// are now separately drawn for top and bottom, instead of relying on
// the default z-order to ensure that bodies are on top of wicks.
//
//#######################################################################
// v 1.2 modified by Osikani, June 15, 2010
//Summary of changes
//
// 1. Modified to run on Ninja Trader 7.0.0.17 Beta
//
//#######################################################################
//
// v 1.1 by Osikani, November 13, 2008
//
//========================================================================
// This indicator is based on the shipped version of the HeikenAshi
// indicator in Ninja Trader 6.5.1000.7
//
// 1. It has been recoded to reduce resource use by optionally
// repainting only bars that are visible in the viewing canvas.
// 2. The indicator will use your defined bar colors for the
// Heiken Ashi bodies.
// 3. The HeikenAshi bar shadows are in the color of the action
// of the actual underlying equity.
// This allows you to see the underlying movement of the
// stock independently of how the HeikenAshi bars behave.
// This may be able to give you advance warning of a reversal or breakout.
// 4. This version has been smoothed to better filter out noise that is
// present even in the HeikenAshi chart.
// It has been smoothed by using the Hull Moving Average, as I have
// found that this average, at low periods, has very little lag to
// what it is tracking.
//
// Modifications:
//
// v1.1
// =======
// 1. Allows one to select the manner in which HeikenAshi bars
// will be painted.
// 2. CalculateOnBarClose set as "false" should now paint bars properly.
//
//========================================================================