help to make altimeter

Unity Engine
,
1

Can some one help me to make an Altimeter?
textmeshproUGUI to display altitude of my airplane.

2

Do you have a specific question / problem?
You have the Y position of your plane. If you want it relative to the ground, cast a ray downwards. Then display this number however you want. Im not very familiar with Altimeters, but if i remember correctly, you have pointers like on a watch, one for kilometers one for hundred meters or so.
So you need to split your number into two values. For a number like 3500, wed want to get a 3 and a 500. To do that simply divide by 1000 and round down to get 3, and calculate modulo 1000 to get the 500.
Now you need a way to display these numbers on your Altimeter. For that you could scale the value to x/360 and use that number in degrees to rotate the pointer to the correct place. So for example, if the large pointer is scaled between 0 and 10, then 3 would be 3/10*360 = 108° rotated.
Put some GUI in the background and that should be more or less it.

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3

thanks

4

Just what Yoreki said… this was my implementation:

     float altitude = ... however you obtain it here ...

        altitude = -altitude;

        var rot1 = (360 * altitude) / 1000;
        var rot2 = (360 * altitude) / 100;

        Needle1.localRotation = Quaternion.Euler( 0, 0, rot1);
        Needle2.localRotation = Quaternion.Euler( 0, 0, rot2);

The Needle1/Needle2 properties are RectTransforms (or Transforms if you prefer) of the two needles.

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5

My quick googlefu says altimeters typically work off of air pressure, and measure altitude above sea level. So I think using world space Y position would be better than raycast to ground level. Convenient it is also easier :wink:

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6

They do indeed… and the published info for an airport gives field elevation so you can calculate where to show up for the pattern.

But radar altimeters behave the way a raycast to ground would behave, like the one in Jetpack Kurt:

https://www.youtube.com/watch?v=6-On25gkWe8

Just a series of raycasts in a 1-unit ring around the base of your ship, and if you are over uneven ground (any one raycast is more than half a world unit than the other), it illuminates the uneven terrain indicator and beeps.

6906158--808847--Screen Shot 2021-03-05 at 3.38.53 PM.png

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7

Yeah he said “airplane” though in the OP :stuck_out_tongue:

Though I wonder what value an air pressure altimeter would say in the vacuum of space?

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8

That kind of questions is what the internet is made for, I suspect it will attempt to reach infinity but will break on the way depending on the maker, this one breaks at 50,000 ft / 15 KM
https://www.youtube.com/ watch?v=fmV9fQseRwE

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9

I would laugh pretty hard if it just said “NaN”

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10

In space, no-one can hear you NaN.

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11

But in space, you also can divide by zero.

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