Paths not rendering correctly at high zoom level?

CesiumJS
1

My “scenario”:

Using attached czml,

in 2.5D or 3D (works fine in 2D),

zoom down to individual block level for the endpoint of the path,

pan map around,

if you’re seeing what I’m seeing, it appears like the endpoint moves around that particular field as you move the map around, i.e. its not fixed on its final position, but moves with the camera.

Has anyone seen noticed this before? I admit its rare people are zooming in that much. Should I open an issue on the project? Any other workaround besides using 2D?

Thanks in advance!

Mike

ps. I’m having trouble posting, trying to remove attachment and put czml directly in post:
{
“availability”: “2013-03-25T17:41:00Z/2013-03-25T17:57:10Z”,
“id”: “0fe2de84-c447-4788-91b5-8839831a61ae”,
“label”: {
“text”: “EXAMPLE”,
“fillColor”: {
“rgbaf”: [0,
0.5019607843137255,
0,
1]
},
“font”: “10pt Lucida Console”,
“horizontalOrigin”: “LEFT”,
“outlineColor”: {
“rgbaf”: [0,
0,
0,
1]
},
“pixelOffset”: [12,
0,
0],
“scale”: 1,
“show”: true,
“style”: “FILL”,
“verticalOrigin”: “CENTER”
},
“billboard”: {
“horizontalOrigin”: “CENTER”,
“scale”: 1,
“show”: true,
“verticalOrigin”: “BOTTOM”,
“image”: “data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAJCAYAAADgkQYQAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAA7DAAAOwwHHb6hkAAAAB3RJTUUH3QMPFAgjDCY/AQAAADFJREFUGNNjYCACMMIYGqc1/qNL3jC9wQhXhE0BskImYqxjwmcKXBHMXryKqOY7ogAAgkUQDFNBvnMAAAAASUVORK5CYII=”
},
“path”: {
“color”: {
“rgbaf”: [1,
0,
0,
1]
},
“width”: 5,
“show”: true
},
“position”: {
“epoch”: “2013-03-25T17:41:00Z”,
“cartographicDegrees”: [0,
-103.0715,
44.14116666666666,
20000,
960,
-93.65152777777779,
42.01859722222222,
0],
“interpolationAlgorithm”: “LAGRANGE”,
“interpolationDegree”: 1
}
}

2

Hi Mike,

What version of Cesium are you using? I believe this jittering issue has been fixed for a while in all three scene modes. However, we are also making pretty significant changes to the polyline.

Dan - can you test in your polyline branch?

Thanks,

Patrick

3

I was able to easily reproduce in Sandcastle in master with the provided CZML. It doesn’t look like jittering to me, but I don’t know what’s causing it.

Dan - to reproduce, just paste the CZML into the “Client CZML” example in place of the CZML already there.

4

Hey Patrick,

I’m using b14 at the moment.

If it helps, I’ve also confirmed the issue in the sandcastle “viewer widget”.

More info if you need it: Using Chrome, Windows7 with an optimus nvidia graphics card.

Mike

5

Mike,

Looking at your packet position, the two points are 960 seconds (2013-03-25T17:41:00Z to 2013-03-25T17:47:00Z) apart. However, that packet has the availability at 970 seconds apart (2013-03-25T17:41:00Z to 2013-03-25T17:47:10Z). We are interpolating 10 seconds past the provided end point, since that’s what the availability tells us to do. Changing the availability to correctly match the data fixes the problem on my machine.

Hope that helps,

Matt

6

To expand on Matt’s answer a bit, the extra 10 seconds that are extrapolated at the end actually makes the line go beneath the surface of the earth. Currently, Cesium primitives are still drawn even though they are underneath the surface, which creates a parallax effect when you pan around because the imagery and the line are actually at different distances from the camera.

7

Scott and Matt,

Thanks for the response and finding the error in the czml! As a follow-on question, is there another way of stopping interpolation into the earth besides using availability?

Mike