Repeating arrows

[Guillaume_Beraudo]

Hello,

I am looking to display arrows along lines.
At the moment, it does not seem to be supported in Cesium.

Here is my analysis of current state and what could be done (including ugly hacks):

• Billboard
  => unusable since it is turning when the camera move

• PolylineArrowMaterial (single head, no drapping on terrain)
  https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/?src=development/Polyline%20Material.html
  => could cut the multiline into a list of segments, each segment would have its head
  => question: would it be possible to repeat the head pattern along the line? Some modulo to add to the shader?

• CylinderGeometry
  in meters so would need duplication to appear at a reasonable width when the distance changes
  the display condition could be used to avoid collision: https://cesiumjs.org/Cesium/Build/Documentation/DistanceDisplayConditionGeometryInstanceAttribute.html

• Model
  in meters
  use minimum pixel size to avoid duplicating the model
  Looks similar to: http://cesiumjs.org/forum.html#!topic/cesium-dev/2s-gA8_rYGk/discussion

Has someone tried addressing this issue already or has some guidances?

Thanks,
Guillaume

[upcwxq666]

I have the same question, i tried to make arrows along polyline by using image material,have you solve the question?

[sam.rothstein]

@upcwxq666

I am not sure if there is an elegant solution to this problem. @Guillaume_Beraudo gave a comprehensive overview of most of the options and each option is clearly flawed. However, one approach would be to create two intersecting lines using PolylineVolumeGeometry.

Here is a sandcastle demo that can get you started:

Cesium Sandcastle

You will need to update the positions coordinates accordingly. If the positions are updated, you should be able to get the arrow shape that you are looking for. Let me know if you have any other questions or concerns.

-Sam

[Kishore_p]

Same here looking for kinda directed path like multiple arrows in between is there such a feature already?

[sam.rothstein]

@Kishore_p

Welcome to the community! I suggest using CZML. This demo shows how to add various kinds of CZML lines to the Cesium World Terrain.

Cesium Sandcastle

To fit this demo to your needs, you will need to update the cartographicDegrees member. Here is some more information on CZML:

CZML Guide

Let me know if you have any other questions or concerns.

Best,
Sam