Major Project Technical Document UCA Rochester – CG Arts and Animation By Paul Lavey How to create HDR Image Based Lighting for a 3D Scene This document will detail the process used to create a custom High Dynamic Range (HDR) photo, which can then be utilized in 3D software as an image based lighting system. This technique uses the following software and equipment. A digital SLR camera with a zoom lens capable of shooting RAW images and a sturdy tripod. A chrome sphere with a sturdy tripod. A copy of HDR Shop A copy of Adobe Photoshop A copy of Autodesk Maya Setting Up The Shoot The aim for this project is to create a computer generated art installation that explores the nature of the uncanny set in a real world setting. In this case the environment is set in a Village Hall in Langley Vale, Epsom. (Fig 1, Fig 2). After scouting the location, the decision was made to place the computer generated uncanny objects in the centre of the hall. The lighting conditions were adequate during the day; however, it changed dramatically over the course of an hour. This meant that the final shoot would be filmed at night so that the light stays constant for the duration of the HDR capture and the live footage. Fig 1. Village Hall Exterior
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Transcript
Major Project Technical Document
UCA Rochester – CG Arts and Animation
By Paul Lavey
How to create HDR Image Based Lighting for a 3D Scene
This document will detail the process used to create a custom High Dynamic Range (HDR) photo,
which can then be utilized in 3D software as an image based lighting system.
This technique uses the following software and equipment.
A digital SLR camera with a zoom lens capable of shooting RAW images and a sturdy tripod.
A chrome sphere with a sturdy tripod.
A copy of HDR Shop
A copy of Adobe Photoshop
A copy of Autodesk Maya
Setting Up The Shoot
The aim for this project is to create a computer generated art installation that explores the nature of
the uncanny set in a real world setting. In this case the environment is set in a Village Hall in Langley
Vale, Epsom. (Fig 1, Fig 2). After scouting the location, the decision was made to place the computer
generated uncanny objects in the centre of the hall. The lighting conditions were adequate during
the day; however, it changed dramatically over the course of an hour. This meant that the final
shoot would be filmed at night so that the light stays constant for the duration of the HDR capture
and the live footage.
Fig 1. Village Hall Exterior
Fig 2. Village Hall Interior
With the positions of the computer generated objects established, the chrome ball is placed in their
location in centre of the room on a tripod at the same level the camera on the live shoot will be
filming. It is important to secure the chrome ball in place and ensure it does not move throughout
the duration of the shoot. Likewise, the camera should also be on a tripod and secured in place as it
will be taking multiple pictures of the sphere at different lighting levels which must align later on.
Figure 3 demonstrates the setup.
Fig 3. Camera and Chrome Ball Setup.
The camera should be placed as far away from the sphere as possible, but still be able to zoom in on
the ball and keep it in full frame. The idea is to keep the reflection of the camera and the
photographer to a minimum.
Camera Settings
With everything in place, check that the camera is:
Set to manual
Set to maximum resolution
Shooting RAW images
Auto focus switched off
Automatic image adjustment switched off
Take a test picture making note of the ISO, aperture and shutter speed setting. Adjust the ISO setting
to a minimum to reduce noise. In this case the ISO is set to 400. Similarly adjust the aperture to a
minimum for a high depth of field, with no depth blur. In this case the aperture is set to 5.6. Next,
adjust the shutter speed to a level that captures a neutral lighting level. In this case the shutter
speed is set to ¼ of a second. This will be the base photo as the shutter speed will be increased and
decreased to over and under expose the subsequent photos. (Fig 4). To create a HDR image you
need a minimum of three images, in this example there are seven at different exposures.
Fig 4. Exposure levels
For the next stage, transfer these RAW images to your hard drive and open up photoshop.