GISBox is a powerful 3D GIS data editing and conversion tool, which can easily convert various geographic data formats into 3D tiled formats supported by Cesium (such as Terrain format). Below are the specific steps to use GISBox to tile DEM files into Cesium Terrain format.

1: Select a new tiling task
Launch GISBox software and find the "Tiling" option on the main screen.

Click "New" to create a new tiling project. This step will initialize the task management screen, allowing you to set tiling parameters and add source files.

2: Select point cloud tile and add DEM file
In the tiling task window, select "Point cloud tile" as the tile type.

Click the "Add file" button and load the DEM file you want to convert. GISBox supports many terrain formats such as GeoTIFF, so make sure your file format meets your requirements.

Once the file is loaded, GISBox will automatically read the geographic information and elevation data.

3: Setting tile attributes
In the tile task window, you can adjust the following attributes as needed:

Color calculation: Selecting the Color calculation option allows you to generate tiles in pseudocolor or true color based on the elevation data.

Vertex compression: Selecting the Vertex compression option optimizes the size of the generated Cesium Terrain data for better loading performance.

Resolution settings: You can set the target tile resolution and level range as needed. This allows you to control the accuracy and size of the generated files.

4: Starting a tile task and monitoring progress
Click the Start Task button and GISBox will start processing and tiling your DEM file into Cesium Terrain format.

In the Task Management window, you can see the task execution in real time, including progress bars and log information.

Once the tiling is completed, a corresponding Terrain folder will be generated and will contain the tile result data.