Bob-omb Raytracing

This is a description of the objectives I completed for my CS 488 Computer Graphics final project. The end goal was to replicate the following image:

Objective 1: Additional primitives

Objective 2: Constructive solid geometry

These objects are constructive solid geometry of a cylinder with a sphere. The top row is union, the second is intersection, and the bottom two are differences.

Objective 3: Bob-omb modeled

The models were made using a combination of the primitives with constructive solid geometry.

• The eyes are toruses unioned with the main body
• The beige fuse is a torus with cubes differenced to cut off parts of it
• The grey blasting cap is a cylinder intersected with a cone, differenced with another cylinder at the top of the cone
• The wind up key is two cylinders unioned with a cube, with two smaller cylinders differenced inside
• The feet are toruses differenced with cubes

Objective 3, 4, 7: Texture mapping, reflection

The other half of objective 3 was modeling the tree seen in the reflection. Since a polygonal mesh of a tree would be too costly, I did it by texture mapping a planar mesh and putting it behind the camera in a way that didn't block the light source / cast shadows. The effect didn't turn out as well as I hoped, so it is not included in my final render.

Objective 5: Anti-aliasing

I implemented anti-aliasing with 3x3 regular supersampling (image on the right). The left is the original for comparison.

Objective 6: Soft shadows

Soft shadows were done through distributed ray tracing with 36 stochastic rays.

Objective 7: Reflection

Objective 8: Glossy reflection

Glossy reflection was also achieved with distributed ray tracing using 36 rays. The perturbations were randomly distributed along a probability density function.

Objective 10: Final scene

Combining everything, below is my rendering of the scene. Total render time: 5 hours 48 minutes, multithreaded on 4 cores.

Extra Objective: Multi-threading

Since I wasn't able to implement grid partitioning (objective 9), I instead implemented multithreading to accelerate my raytracing. Below is a graph comparing the time it took to render the macho-cows image with anti-aliasing turned on for differing numbers of threads.