# Talk:Bounding Volumes

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Chris Taranta, 8.16.11 Thanks for making a page on this topic. As a high school mathematics teacher, the topic is new to me, and I enjoyed learning about it. As I read and edited your page, I sometimes needed to do further research on some of the more challenging topics such as ray tracing. My comments reflect that knowledge base and are from the perspective of someone interested in the topic but not very knowledgeable about it. As such, I am looking for clarity in the basic explanations. I have edited the first half or so of the piece and will try to finish it later today or early tomorrow morning.

### Basic Description

P1S4 (Paragraph 1, Sentence 4) I would change the beginning of this sentence to "Bounding them in simple geometric shapes lowers the computation cost..."

The video is confusing to me. What is the purpose of the small circle of circles in the middle? Why does the larger box flash on occasionally? There needs to be a clearer connection between the text and the video.

### A More Mathematical Explanation

P1S1 I would change " a graphical image on the screen" to "a computer graphics image."

P1S2 "used display simulated optical effects". Can that be changed simply to "used to simulate optical effects"?

P1S3 Is the term "surface" of the object complete enough to determine how it is rendered? It might be helpful to describe what "surface" means in this context, because it is the interaction between the light and the surface elements (color, tranlucency, etc.) that determines how best to render it.

P1S4 Isn't the computational cost increased by the number of tracings that don't hit the object, not the vertices? Wouldn't the vertices piece apply to collision detection, not ray tracing?

P2S1 Given that you are beginning a new paragraph, you need to reiterate the concept instead of saying "The same concept."

P2S5 Change "from the center of one.. is bigger" to the "the distance between the centers of the spheres is greater than the sum of their radii."

P2S6 Change "if they colliding" to "if the objects are colliding."

P2S7 Change "The first step" to "This step"

### Different Bounding Volumes

The convention we use as Swarthmore is that every image after the initial image has an image number.

1. Bounding Box

S1 Change "It" to "A bounding box."

S2 Why do you use cup and table for this? This seems like a rare use of a fairly commonly used object.

S3 "Bounding boxes may be axis-aligned or oriented (non-axis aligned)..."

2. Bounding Sphere

P1S1 Again, don't start with "It." The word "encapsulate" should be plural.

P1S2 I think you need only one image, not four, to demonstrate your point that there is a lot of empty space in the sphere.

P2S3 Change "cubiod" to "cuboid."

P2S4 Only two images, not four, are needed.

P3S3 Change "that works for any figure" to "that works for all figures."

3. Other Bounding Volumes

P1S2 Change "Other frequently used are" to "Others frequently use include..."

P1S5 I would delete this sentence. I assume it's rarely used and so does not warrant inclusion.

### Why It's Interesting

S1 Change "is used" to "are used."

S4 Change "distance with the wall" to "distance from the wall."

S5 Aren't bounding volumes useful because they save computation time? Make this a stronger sentence.

### How the Main Image Relates

Why is this section included?

### Messages to the Future

I made a list of possible improvements, including topics that deal with Bounding volumes, but should be on their own page.

### References and footnotes

All the images that are not mine are referenced.

### Good writing

Context
This is a graphics helper page. This method is widely used.

Quality of prose and page structuring
I put all the shapes in bold and the explanation under it.

Integration of Images and Text
I have small images with the bounding shape, and then big ones that are hidden for the spheres.

Connections to other mathematical topics
This page has to do with simple geometry, so it's for high school students and up (labeled as such on the page).

Examples, Calculations, Applications, Proofs
There are graphical examples, as well as a video.

Mathematical Accuracy and precision of language
Ray tracing and collision detection is explained well, in a straight forward manner.

Layout
The text is in short paragraphs and broken up into sections by shapes.