About Polyline Dashed

CesiumJS
1

Hello, everyone.

I only look at it every day, but there is an issue, so i heve a question about dashed line.

Express the dot or dashed line on the road.
However, the problem is that is moves alone with the camera movement as blow.
< case shot -1 >
dash_scroll

< case shot -2 >
dash_scroll2

Cesium 1.82 and using normal polyline/Cesium.PolylineDashMaterialProperty.

what i want is not to move.

what would be the solution?

2

Hi @lion.leekyungseok,

Welcome to the community and thanks for sharing! I really appreciate that you added some screengrabs as well. However, I am a little unclear as to what your intended use case is. Can you elaborate on the behavior that you expect from the dashed polyline?

-Sam

3

Thank you for your answer.

Ah… I was waiting for the person who knows the answer and implemented it as corridor instead of polyline.

The results are as follows.
< polyline dash > - fallow camra
dash_scroll2

< corridor dash > - static
dash_scroll_corridor2

I don’t know what the performance difference is, but anyway, I’ve reached my goal, so I decided to use it as it is.

Mr. sam.rothstein Thank you again for your reply.

1 Like
4

Hi @lion.leekyungseok,

Understood :+1:

-Sam

5

For future reference.
One potential solution is using GridMaterial.

entity.polyline.material = new Cesium.GridMaterialProperty({
            lineCount: new Cesium.Cartesian2(20, 0),
            cellAlpha: 0,
            lineOffset: new Cesium.Cartesian2(0, 0.5),
            lineThickness: new Cesium.Cartesian2(10, 0)
        });

This creates a dashed line that does not move with camera.

image
image813×682 35.4 KB

When the segments of the line are not the same length, wacky things happen…
image
If your line has roughly same length segments, or it is a single segment, then it should all be good.

This will look similar to ImageMaterialProperty, given a texture of a single dash, but unlike an image of a dash on repeat, the dashes in this case will have no issues with changes in width.

Hope this helps someone.

1 Like
6

thank to max_izrin very mush for your reply.
your reply is precious anyway.