---
title: "Irradiance Map Viewer"
canonical: "https://documentation.chaos.com/space/VRAY4TOOLS/117637173/Irradiance%20Map%20Viewer"
format: markdown
---
This page contains information about V-Ray's standalone Irradiance Map Viewer tool.   Overview The irradiance Map Viewer is used to view, merge, and save irradiance map files created by V-Ray. It allows the user to navigate around a 3D projected version of a scene to view where GI samples were taken during the rendering process. Note:  The viewer is a standalone program and does not require the V-Ray host application (3ds Max, Maya, MODO, etc.) to be running.   Location By default, the imapviewer application is included with the V-Ray installation. See its location according to your host app: V-Ray for 3ds Max V-Ray for Maya V-Ray for Houdini V-Ray for SketchUp V-Ray for Rhino V-Ray for Cinema 4D   Usage   There are several methods of running the irradiance map viewer, which are outlined below. The simplest way is to double-click the  imapviewer.exe  file. This will bring up an  Open File  dialog box that lets you browse for a light map to open. This is the same as starting the irradiance map viewer from the Start Menu. The menus of the program allow you to do various things with the light map (merging and saving, etc). You can also run the irradiance map viewer from the command line. In this case, there are several possible choices: If you type just > imapviewer on the command line, this is the same as double-clicking the file. It brings up the  File Open  dialog for selecting an irradiance map or a light cache map file. You can also type > imapviewer  <filename>   where   <filename>   is the name of an irradiance map or a light cache map file. This file is opened automatically. A third way is to use the viewer to merge several maps into one: > imapviewer -load  <map1>  -load  <map2>  ... [-save <finalmap> ] [-nodisplay] This loads the specified maps and combines them into one light map of the same type. If the -save option is specified, the result is written to the given file. If the -nodisplay option is specified, the resulting map is not displayed (otherwise, the viewer displays the final result).  Options Option Description [-incremental] -load <filename> {-load <filename>} [-save <filename>] Merges the specified irradiance/light maps and writes them to the specified file. If the -incremental option is specified, the imapviewer discards samples that fall in areas where there is already sufficient information. This option must be specified before any -load options. -info Prints out information about the current irradiance map. -noDisplay When this option is specified, the resulting map is not displayed (otherwise, the viewer displays the final result). -up_axis [z|y] Chooses the up axis (default is z). -convert <filenameFrom> <filenameTo.pts> [-rgb] Converts the irradiance map file into a PTS file. -help Prints a help message.