Summer Code Sprint Trip Report


For the Wednesday through Friday after Memorial Day Weekend, the Cesium team worked from beautiful Wildwood, NJ, down by the shore, for our semiannual code sprint. The code sprint is designed to be three intense days where team members pick projects with immediate impact. It also designed for socialization and ramping up for new team members.

This was my first time doing a code sprint, and I’ll say that besides the focused atmosphere it provides for getting work done, the team building that happens during these events is invaluable. Josh and Gary just started a little over two weeks ago and it already feels like they’re part of the Cesium family.

coding-outside Gary, Josh, and Sean enjoying the outdoors.

We got a lot done and made huge strides on some big up-and-coming updates that we think the Cesium community is going to be really excited about.


  • Hannah and Matt added support for Box, Cylinder, and Corridor Entities into CZML. #3989
  • Dan made the Cesium map rotatable in 2D mode (#3990) and added Earcut into Cesium for more robust and about 2x faster polygon triangulation. #3998
  • The team even managed to release Cesium 1.22 during the sprint.


  • Patrick has been hard at work finalizing the glTF spec from 1.0 to 1.0.1. The focus of this update is on rigorously defining corner cases to aid in validation.

glTF and 3D Tiles

  • I finalized my work on adding support for the glTF WEB3D_quantized_attributes extension to Cesium (#3891). Expect a blog post from me within the next few days about what that means for Cesium and for 3D Tiles.
  • Matt prototyped converting CityGML data to 3D Tiles and has provided some gorgeous screenshots of the rendered New York data set.

Statue of Liberty Statue of Liberty CityGML

Yankee Stadium Yankee Stadium CityGML


This a fairly young project designed to optimize glTF assets, which got a lot of love during this code sprint. Check it out!

  • Josh and Gary added support for KHR_materials_common into the pipeline. #55
  • I worked on adding support for generating quantized glTF models. #56
  • Josh, Gary, and Sean put together a shiny new command line interface for the pipeline (#53) and worked on adding the pipeline optimizations into the Cesium website model converter along with OBJ2GLTF for .obj 3D model support. Expect to hear from them soon as those changes get finalized.


  • Tom Ped wrote a WebStorm plugin for switching back and forth between a source file and its test file (#3996), he also started work on some Cesium wearables.


We got a lot done and laid the groundwork for some big changes, so stay tuned for lots of exciting stuff moving forward.

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