Re: How to get heading, pitch and roll from the two points

[Gabby Getz]

If you have the two points, you can compute the vector direction by subtracting one from the other.

Here's a function you can use to get a rotation matrix from the origin and the vector.

Lastly, you can use Quaternion.fromRotationMatrix to get a quaternion, and  HeadingPitchRoll.fromQuaternion to get the HPR object.

On Tuesday, July 31, 2018 at 12:15:44 PM UTC-4, Alen Kelemen wrote:

To represent a valve in a pipe I want to make two cylinder entites or to insert a model. To accomplish any of that I need position and orientation.

So I have two points representing start and end of a valve.

 Position is determined like this:

            var start = Cesium.Cartesian3.fromDegrees(czml[0], czml[1], czml[2]);//start point

            var end = Cesium.Cartesian3.fromDegrees(czml[3], czml[4], czml[5]);//end point

            var dist = Cesium.Cartesian3.distance(start, end);

            var mid = [(start.x + end.x) / 2, (start.y + end.y) / 2, (start.z + end.z) / 2 - dist / 4];//middle point == position

I have trouble to determine heading, pitch and roll of the valve from start and end point.

My code so far (not giving a correct hpr)

//get angles in all three planes
xDx = (end.x - start.x)

xDy = (end.y - start.y)

xDx = (end.x - start.x)

xDz = (end.z - start.z)

xDy = (end.y - start.y)

xDz = (end.z - start.z)

var heading = Math.atan2(xDy, xDx)

var pitch = Math.atan2(xDz, xDx)

var roll = Math.atan2(xDy, xDy)

var hpr = new Cesium.HeadingPitchRoll(heading, pitch, roll);//not OK

var position = new Cesium.Cartesian3(mid[0], mid[1], mid[2]);//position is ok

var valve = entities.add({

                id: "Valve" + feature.getId(),

                name: "",

                description: "",

                position: position,

                orientation: Cesium.Transforms.headingPitchRollQuaternion(position, hpr),

                cylinder: {

                    length: dist / 2,

                    topRadius: 0.0,

                    bottomRadius: radius_m,

                    material: Cesium.Color.BLACK

                }

            });

With this code I get incorrect orientation of the cylinder (black):

My question is: what is the correct way to get heading, pitch and roll from the two points.

[Alen Kelemen]

Dana petak, 3. kolovoza 2018. u 17:54:05 UTC+2, korisnik Alen Kelemen napisao je:

Thank you Gabby.

I solved the issue somewhat different, but anyway your advices are pressius.

Especially when there are no courses or comprehensive book about Cesium API (as far I know).

[ulrich...@dimetor.com]

Hello Gabby,

I'm trying to follow your approach to determine the orientation between two points but I don't get correct results. I think the function you referring to is `Cesium.Transform.rotationMatrixFromPositionVelocity`?

I created a Sandcastle example with my code (the blue cone should point to the green 'target' point):

https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/index.html#c=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

Do you know what I did wrong?

Thanks!

Ulrich

[m...@ulrichlehner.com]

Nevermind, I got it working:


https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/index.html#c=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

(my previous example applied a wrong transform for the orientation)

[Omar Shehata]

This is great! Thanks for posting your solution. I imagine this will be useful to a lot of others as well.

[artille...@gmail.com]

This is a great work of two points and a cone orientation drawing. Thanks for sharing your solution!

On Thursday, February 28, 2019 at 7:03:38 AM UTC-5, m...@ulrichlehner.com wrote: