Friday, 22 February 2013

Scene Inside, Light Outside!

Here's our first lighting assignment of Semester IV! So we started using Mental Ray [yay!], and the first challenge was to achieve a realistic indoor scene which had to be lit by natural/outdoor light. This was done using GI and FG [Global Illumination and Final Gathering]. The image on the top is the original image, rendered in Mental Ray. The second image was rendered in Mental Ray and then edited a bit in Photoshop [bringing out the shadows and highlights, and making it a warmer, evening tone].

[Read more below]

Assignment Description:

Using Global Illumination and Final Gathering, render an indoor scene which is being lit by natural light [external light source], using Mental Ray.

Completion and Render Time:

For my very first organic scene/lighting project, I spent about 3-4 days working on this [each day about 5-6 hours]. The total render time for this scene, with GI and FG enabled, was...believe it or not...1.5hrs! I'm not sure why it took so long...maybe because I went crazy on the paint effects!

How It Was Made:

This was quite a challenge, considering we had to MODEL our very own scene [aside from texturing and lighting it]. The rocks and cave walls were modelled with ease, and the stalactites [or are they stalagmites?] were made using a displacement map. The wonderful oak tree and lush, green grass were just part of Maya's Paint Effects [sorry to disappoint you!]

However, the most challenging part of this project was achieving the volumetric lighting [the FOG]...I had to keep watching tutorials and playing around with the settings in Maya myself, until I finally achieved what I wanted...since Mental Ray doesn't recognize fog from spotlights, I created a few volume primitives [cubes] and messed around with the [cubeFog] shader settings. Then, I created some large planes with holes in them and placed them near the openings of the cave, and I aimed the lights through the holes. Finally, by selecting "Illuminated" in the cubeFog shader settings, the fog was limited to the amount of light which was passing only through the holes in the planes. [It's kind of complex...but it worked!]. A lot of inspiration for this scene came from Shrek's swamp and the Fountain of Youth.

Final Words:

Overall, the modelling and texturing was quite easy and straight forward. The lighting wasn't too difficult, but it was time consuming, considering this is the first time I'm rendering using Mental Ray with GI and FG. And the fog...was brutal! Hopefully I can find a better way of generating it without going through all that unnecessary hassle!

Stay tuned for my next lighting assignment: IBL [Image Based Lighting!]
Until next time,
Nathanael Xavier