HDR Imaging and What it All Means

This week was a bit different than most. Unfortunately, our professor was out sick (get feeling better Professor Glover!), but the substitute did her best.

HDRI

HDRI, or high dynamic range imaging, is a set of techniques that can be used to allow for a much greater range between the dark and light images in a photograph. This will come in handy for our After Effect’s built set for the movie that we a continually working on. Using the keyed up footage from last week, we are able to insert an image into the alpha channel of the movie. But first comes choosing a movie. This is the image I went with:

I then opened it in photoshop and, after making a seperate layer, went to Image>Adjustments>Brighten/Contrast. After lowering the contrast, I then saved the image as a seperate document, re-opened the original, then created an image with a higher contrast and saved. With these two images, we will create an HDRI. Go to File>Automate>(choose the two files)>Merge HDRI and press “ok”.

A window will then open up that will allow you to adjust the now HDR image even further. After all is done, you must save as either a bitmap or TIFF.

AFTER EFFECTS

With the movie open, you are able to just import the image and drop it into the timeline. And here is the final outcome:

.aep File:

.flv File:

IMAGE BASED LIGHTING

So now, with the environment in place, we are ready to set up the cameras for our VFX movie! Open up maya and go into render settings. Under the Mental Ray option, go to Indirect Lighting>Create Image Based Lighting. You can then load the HDR image into the load prompt. Now, open the hypershade. Create a mental ray node>Lenses>mia_exposure_simple. With the rendering camera’s attributes editor open, drag and drop the newly created  lense into the lens shader. With the new exposure set to the lens, you can delete the sphere created by the image based lighting and create a new surface sphere. And, WALLAH!, you have image based lighting.

HOMEWORK

As far as the substitute could tell, we are to create an environment for the footage and ready the inner maya HDRI.

HDRI Maya file: http://www.mediafire.com/?mivxm3t4mzi

Until Later!