# Questions tagged [geometry]

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24 views

### horizontal angle of view based on distance from window [closed]

I am looking for an equation to provide me the angle of view based on a distance from a window. I'm only interested in the horizontal not the vertical.
823 views

### Wrap a geodesic dome with a poly sheet: Minimize overlap & loose areas

I want to make a geodesic dome greenhouse (16ft wide, type: 3V 5/8). Source: http://geodesicdomes.ca/wp-content/uploads/2009/12/domes-fullsize.jpg I would cover a geodesic dome frame with clear ...
55 views

### Arc subtended by stretching of a conical spiral spring

I'm trying to work out the angle subtended by the stretching of a conical spring and I have a solution but I'm not 100% sure about it so would appreciate some feedback. An Archimedes spiral spring is ...
89 views

### How to calculate miter angles for an angled stretcher

See the image below: When I lay this out in Fusion, I can get the angles but I can't figure out how to calculate it mathematically. The goal is to have the angled stretcher fully contact the upper 45&...
93 views

### Equation used to obtain the adjustment angle of a pivoting lid support mechanism?

The following image shows a CAD model in its folded and unfolded form. I was able to successfully give it the ability for it to be adjusted between a 25 and 45 degree form, at 5 degree increments; ...
72 views

### How to trace a square with a reuleaux triangle

I am trying to trace a square (with rounded corners) using a reuleaux triangle and a single (circular rotation) motor. I've seen many animations (example) of this but do not understand how to make it. ...
32 views

### Meshing Error near Leading and Trailing edges

I am trying to mesh the propeller geometry in the Ansys meshing tool. At the leading and trailing edges of the propeller, mesh goes out of boundary. I did a geometry check of the CAD model in ...
456 views

### Calculating area moment of inertia for a beam with underslung plate?

In a number of designs, a beam will have an underslung welded plate attached, as shown below: In this sketch, a symmetrical standard steel beam/column of dimensions H1 x B1, with web and flange ...
30 views

### Is a pyramid considered axisymmetric? Why so?

I read a source, I will not reference the source on this platform. They stated a pyramid is axisymmetric. Can you explain why if yes?
29 views

### When calculating a car's suspension caster, after turning the steering wheel 20 degrees, why multiply by 1.5?

To calculate caster of one side of a vehicle, the steering wheel is turned 20 degrees to the left, and the camber is obtained; this represents the 'in' value of the front right tire. Then the steering ...
619 views

### What makes scooters unstable at high speeds?

Scooters and skateboards are obviously meant for slower speeds, below 5 MPH. Typically if you go faster than that, it becomes harder and harder to control the scooter, and you will fall off. An ...
647 views

### How to calculate meters per pixel for a given camera?

I am stuck on this problem for a while: I have a square-shaped camera, with: 1000 pixels on vertical side 1000 pixels on horizontal side I want to know the number of meters per pixel depending of ...
46 views

### How could I get the coordinates of the circumscribed circle giving the 3 points coords?

I have the coordinates of 3 points thrgouh which, a circle should pass . Having the coordinates of the points in 3D, how could I have the coordinates of the center of circumscribed circle ? also : if ...
121 views

### Difference in Diameter calculation using Solidworks and manually

When I try to create a flat form of a archimedes screw using Solidworks it gives me a diameter different from what is calculated manually basically using a Pythagoras Theorem. Can anyone explain the ...
27 views

### Program for creating a cylinder given its axis, center and radius?

I have data with the following normalized values: Unit vector for cylinder axis: -0.00270666, -0.01226211, 0.9999212 Normalized coordinates for cylinder center 0.01412114, 0.01074875, 0.00017004 ...
65 views

### Calculate area of mesh?

I have expanded steel mesh that I use to make garden cages: I would like to know how much sunlight the mesh blocks. I think I need to calculate the area that the mesh takes up (per square inch) and ...
666 views

### How can I draw Voronoi regions in curved surfaces in AutoCAD?

How can I automatically compute and draw/display the Voronoi diagram of a given set of vertices on a surface in AutoCAD? A "Voronoi Sketch Generator" is the best I could come up with on a google ...
147 views

### Turbocompressor spool geometry

How come axial compressors always narrow and turbines always widen towards the rear? From what I know: The speed of sound of air increases with temperature, therefore increases (decreases) as it goes ...
73 views

### Building a half-arch of a specific height, while consistently using an angle divisible by 90

I am trying to construct a lift handle in the CAD Sketchup. The circled part of the image shows the arch I'm referring to. The program, Sketchup, has a 'tool' called push/pull, and another tool ...
370 views

### Do outer fillets|chamfers also reduce stress as inner ones do?

I kind of have an intuition or at least imagination about how fillet|chamfer of inner edges|vertexes reduce stress (concentration). But does that apply to outer edges|vertexes aswell? Maybe to a ...
128 views

### Boolean Geometry Help [closed]

I just don't get the concept of Boolean Geometry... Can you help me understand how to solve these homework problems? Thanks!
19 views

### How to find the nearest locations around a given latitude and longitude point? [closed]

I have a database of locations. Each location is a latitude and longitude pair. Now for each query, I want to get top "X" nearest locations around a given latitude longitude point. How do I actually ...
63 views

### Calculate attitude quaternion from 2 vector measurements

I am using a method proposed by R. G. Reynolds to estimate attitude based on two vector measurements, taken from: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990052720.pdf Suppose we ...
890 views

### Calculating moment of inertia for a hollow discontinuous circle?

This is a pretty simple problem, but I'm just not sure how to go about it. I want to find the moment of inertia of a discontinuous hollow circle. But since the shape is so irregular, I'm not sure how ...
1k views

### Why are Whitworth threads angled at 55°?

You're probably thinking, "Well.. Why not? It's gotta be something.." Right? But 55Ā° is kind of an odd angle if you think about it.. and it does seem like a pretty specific choice considering a ...
84 views

### How maps of globe, country or region were created few decades/centuries ago when modern technology like today did not exists?

What techniques were used to create the maps of a world, country or region when satellite or similar technology did not exists few decades or centuries ago?
96 views

### What does this equation mean?

$$\propto \dfrac {\text {Cross-Sectional Area}}{\text {Volume}}$$ I've seen this equation on my textbook (physics). Let us imagine that there are two pen with $7$ and $3$ lenght. Which is harder ...
106 views

### Diesel injector nozzle geometry

I thought of an injector nozzle for a diesel engine with an alternate combustion chamber format (somewhat like a Heron combustion chamber), and would now like to get an estimate of the size of the ...
103 views

### What is the most accurate geometry to represent earth

Currently software and maps represent earth in many different ways, the latest is Point Clouds as this is the most common surveying tools currently available. For the needs of visualisation, ...
202 views

### Advice for designing internal structure of glider wing

I am interested in designing a scale model semi-monocoque wing for a glider. I've done some research on the framework and internal structure. I have found out about the spars, ribs and stringers and I ...
96 views

### What is the deflection of planet-ring Gear Mesh along the pressure line and the position of the Plant gear?

For a Sun-Planet mesh in a planetary gear train, there will be a deflection $\delta_{sn}=\delta_{s}-\delta_{n}$ along the pressure line and the position of the planet will be determined by $\psi_{n}$, ...
90 views

### Graphene distribution over a sphere

How much graphene is required to coat a 5 inch (diameter) sphere if the graphene layer must be 35 nanometers thick?
77k views

### Moment of Inertia of a Rectangular Cross Section

I have a question that is annoying me for a long time. I know that I can calculate the moment of inertia of a rectangular cross section around a given axis located on its centroid by the following ...
601 views

### How this radio knob converting a rotation into a straight-linear motion?

Few months ago I opened the boards of an old, scrap radio-cum-tape-recorder (Philips DR183); whose tuning knob (that adjusts the gang); was very peculiar. ( * I did not found its datasheet on web) ...
543 views

### What is a void in CAD

I'm using existing architectural designs and some mechanical designs too, all CAD files in formats *.dwg, *.dgn and the drawings have smart solid geometries including voids. Using CAD software what is ...
247 views

### How should I calculate the centroid of a hollow structure when analyzing a wind load?

I am trying to solve the following problem: A masonry chimney having the shape of a conical frustrum is 25 m high. The external diameter at the top and internal diameter at the bottom is 2 m. ...
1k views

### How to design a swivel connection for a single wheel trailer?

I'm trying to design a single wheel trailer for my underpowered VW, much like this one. Unlike a conventional trailer, it is attached to the car at two points. To prevent the wheel from dragging, it ...
4k views

### Is a circle the strongest 2D shape for containing internal pressure?

I understand how a circle (or sphere if you want 3D) is the best shape for holding a vacuum inside a container, but what if you wanted to have a large positive pressure inside of the container instead ...
881 views

### AISC Section Modulus numbers

Why does the AISC handbook only list one figure for Section Modulus for shapes such as Angle(L) steel? Shouldn't there be two? The steel is asymmetric. Is the figure given just the Delta to the ...
101 views

### Lengths of Connectors in Steering Linkage

Below is a picture 4-wheel vehicle steering linkage. I figured that in order to steer correctly $(W+D)tan\theta_1=Dtan\theta_2$ where $\theta_1$ is the angle of the outside front wheel, $\theta_2$ is ...
358 views

### How thick does an aluminium vacuum cylinder have to be?

Take a hollow aluminium cylinder with outer radius $r$ and length $h$, capped with two circular endcaps. How thick does the aluminium have to be, that is what is the inner diameter of the cylinder, ...