To follow correctly this tutorial, download this scene.

Extract the content to a directory.

In ths tutorial we will use HDRSHOP. With this program and the plugin Lightgen we will get to fake with a sphere of lights, the illumination of an HDR image.

Now, download an HDR image like this.

When downloads are finish, execute HDRSHOP and the image that you have download.

Like you can see it's an angular image. We are going to transform it to a Panoramic image.

Click on Image --> Panoramic --> Panoramic Transformation.

In the new window configure it like in the image. We are converting the image from a Light Probe (Aungular Map) to a Latitude/Longitude.

We don't need too much resolution for this task, and a re values like 128x64 it's OK.

This is the type of image that we need to invoque the Lightgen plugin. This plugin creates a MEL script that creates a sphere of lights according the image HDR.

We have to click on Plugins --> Lightgen_plugin.

Now, will appear a window like the next.

In the window we have to give a name to the future script and select the MEL format.

Choose the number of lights that you want (more lights, more shadows, more render time).

Activate the option Scale total light output and put a value between 1 and 3 in the Desired total light intensity box.

Click on execute and wait until the program calculates de result.

A window like this will appear, but it's not important. Click on the button and when the program finish, close HDRSHOP.

Now, in Maya, with the scene loaded, go to the script editor click on source script and execute the MEL created.

In the workspace will appear a few lights and a locator (lightgen_control).

Select the locator and adjust the Dimmer value (higher value, higher light intensity).

To begin, put a value like 3.5.

Launch a render and see the results of faking HDR with maya's native render.