Thursday, October 17, 2013

Snow globes

Just in time for Christmas.... oh wait, isn't there another Holiday or 2 between now and then?  Ah who cares about those holidays, we all know the only holiday that counts is the one where people spend the most money.  At least that's what stores seem to think.  Honestly I love Halloween and Thanksgiving, but for my latest project in my Renderman class (VSFX 319), we had to model snow globes.  While one girl in class actually did do a Halloween themed snow globe, I couldn't help but equate snow globe with Christmas.  So I decided to model Santa's Workshop.

The assignment was specifically to learn IBL (Image Based Lighting), which is a way of taking a very specific image (HDRI) of an environment and putting it in a scene, allowing the computer to calculate the lighting of the scene based on the values in the image.  It's kind of like taking an environment and putting it into your scene.  Sounds magical, but it is really not going to look right.  Imagine taking motion capture data and just leaving the raw data on the character and displaying that in a movie... it doesn't look good, trust me.  Animators need to adjust and tweak and fix the raw data into something that looks good and suitable for the character.  Just like that, I have to take this IBL and tweak it, add lights, adjust values, etc. to make the lighting look realistic like the object belongs in the scene.

We also had to use a specific Global Illumination technique, and actually got to play with 2 methods of it.  One uses Point Clouds to calculate illumination and occlusion, while the other uses ray tracing.  The point cloud based method is faster, stores the data to speed up processing later on, and developed by Pixar, but prone to inaccuracies.  The raytracing method is longer, but more accurate.  I used a hybrid technique where I raytraced, and then stored the data to speed up the processing.  It took about an hour and a bit to render these, but it was surprising to see some students with render times ranging from 20 minutes to over 4 hours!

I haven't quite dialed in the lighting all the way yet, and I am still working on the camera focal length (so expect more updates on this one later), but for now, I am relatively pleased with the results of my work, but I'm not going to leave it there.  For now, though, enjoy these three images.  Ho ho ho.

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