In this tutorial you can learn how you to set up and light a 3ds max exterior scene with a HDRI Skydome and mental ray. While hdri lighting is not very complicated it´s necessary to know some details in order to get a useful result.
The VP HDRI Skydomes have a very high dynamic range, which is best to create sharp sun shadows. Also they have an accurate white balance that will bring convincing and colorful lighting into your scene with a few clicks.
Basically you just need to follow 3 main steps: First to create a standard skydome light, then create background map and third the proper exposure settings.
(1) Create a skydome light
First you need to create a standard Skylight and place it anywhere in the scene. Then you need to add the hdri skydome to the texture map color slot of the Skylight so the skydome is used light up the scene. You can use a simple bitmap map for the moment. We will later see how you can adjust gamma and exposure within this slot, but for now, let´s keep it simple. Make sure that you set map amount to 100% and check “[√] Sky Color” in the Skylight.
Within the bitmap shader you need to set the mapping correctly, otherwise the lighting will look strange. Set the mapping to Environ and Mapping type to Spherical Environment.
(2) Use the same hdri for the background
You can skip this step if you want to use specific backplates for your background or if you add a background later in compositing / photoshop. If you want to use the same hdri skydome also for the background, here are some additional steps.
Within the Environment and Effects add a new map called Gamma & Gain. It´s a standard map that can be used to change the gamma and exposure on another map. Within this map in the input map slot create an INSTANCE of the original hdri skydome bitmap that you created before for the skylight. If you create a copy, you can later change the direction of the background independently from the skylight light direction. If you create an instance, both will be rotated in sync.
Now the skylight and the background are prepared. If you render now, you will probably get wrong lighting and over- or underexposed images. So we need to adjust the camera / exposure settings to match the lighting and background.
(3) Setup the photographic exposure
Within the Environment and Effects dialog, choose “mr photographic exposure”. This will give you access to color mapping, exposure and other parameters that need to be adjusted according to your light and background setup.
To match the exposure to the light you have to adjust the following parameters:
- Skylight strength
- Exposure Value (EV)
- Gamma Settings
These are photographic parameters and work the same way like a normal camera. There are lots of tutorials on the web explaining photography and we don´t want to go into too much detail here. As the settings may vary strongly depending on the used hdri map, it´s not very useful to define specific settings here. But a good starting point for the EV would be something between 5.0 and 15.0 with a Skylight value of something between 1.0 to 10.0. Anyway it´s necessary to play around with these parameters in order to get a good result.
All of the VP HDRI Skydomes include 3ds max scenes with proper light and camera settings, so you can just go ahead and start rendering your own scene.