Calculate the area intersected by a sphere and a rectangular prism

  • #1
guv
123
22
Homework Statement
I am trying to figure out the area on the surface of a sphere as a result of the sphere intersecting a much smaller rectangular prism.
Relevant Equations
N/A
Think of a 3D rectilinear grid made of these rectangular cells, some of the cells will intersect with the sphere. I am trying to compute each intersecting area and the total sum. Ideally the total sum of the intersecting area should be close to ##4 \pi r^2##. I have not found any literature discussing this problem. Part of the problem is that the polygon on the sphere as a result of the intersection is not necessarily made of geodesics. Moreover, part of the rectangular prism can embed inside the sphere causing irregular intersecting shape. I am looking for ideas how to get this done correctly. Has anyone seen any problem. I would imagine this might be useful in computer science, but obviously people there are not too concerned with accuracy of the result. Thanks!
 
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  • #2
guv said:
Homework Statement: I am trying to figure out the area on the surface of a sphere as a result of the sphere intersecting a much smaller rectangular prism.
Relevant Equations: N/A

Think of a 3D rectilinear grid made of these rectangular cells, some of the cells will intersect with the sphere. I am trying to compute each intersecting area and the total sum. Ideally the total sum of the intersecting area should be close to ##4 \pi r^2##. I have not found any literature discussing this problem. Part of the problem is that the polygon on the sphere as a result of the intersection is not necessarily made of geodesics. Moreover, part of the rectangular prism can embed inside the sphere causing irregular intersecting shape. I am looking for ideas how to get this done correctly. Has anyone seen any problem. I would imagine this might be useful in computer science, but obviously people there are not too concerned with accuracy of the result. Thanks!
If the polyhedron is inside the sphere the only possible points of intersections will be at points or edges on the polyhedron where two or more polygons meet. At least that's what I come up with based on your description.
 
  • #3
How are these figures given? Do you have their equations, or are they given in a different format?
 
  • #4
guv said:
Has anyone seen any problem. I would imagine this might be useful in computer science, but obviously people there are not too concerned with accuracy of the result.
They call it interface reconstruction and are very concerned with accuracy vs. computational cost.
 
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  • #5
Take a look at the pictures attached, I am guessing 'interface construction' is the algorithm that results in what we see in the pictures. How about area calculation? Is there any literature on how to find the intersection and area in the general case? The intersection looks like a simpler problem, the area seems difficult.
 

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FAQ: Calculate the area intersected by a sphere and a rectangular prism

What is the general approach to calculate the area intersected by a sphere and a rectangular prism?

The general approach involves using geometric principles and calculus. First, you need to establish the equations of the sphere and the rectangular prism in a common coordinate system. Then, you determine the volume of the intersection by integrating over the region where the two shapes overlap. The area of the intersection can then be derived from this volume.

Can the intersection area be calculated using simple geometric formulas?

No, the intersection area of a sphere and a rectangular prism typically cannot be calculated using simple geometric formulas due to the complexity of the shapes involved and their intersection. Advanced methods involving calculus and numerical integration are usually required.

Are there any software tools that can help calculate the intersection area of a sphere and a rectangular prism?

Yes, there are several software tools that can help with this calculation, including mathematical software like MATLAB, Mathematica, and computational geometry libraries such as CGAL (Computational Geometry Algorithms Library). These tools can handle the complex integrals and numerical methods required for accurate calculation.

What are the key parameters needed to calculate the intersection area?

The key parameters needed include the radius and center coordinates of the sphere, and the dimensions and position of the rectangular prism. These parameters are essential to define the equations of the sphere and the prism in the same coordinate system.

How do you handle cases where the sphere and rectangular prism do not intersect?

If the sphere and rectangular prism do not intersect, the intersection area is zero. To determine if they intersect, you can check the minimum distance between the center of the sphere and the faces of the rectangular prism. If this distance is greater than the radius of the sphere, there is no intersection.

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