Data streaming: Levels of detail
This section discusses the Levels of detail (LOD) datasets (from Gaia DR2 on) where not all data fits into the CPU memory (RAM) and especially the GPU memory (VRAM).
In order to solve the issue, Gaia Sky implements a LOD structure based on the spatial distribution of stars into an octree. The culling of the octree is determined using a draw distance setting, called
Balancing the loading of data depends on several parameters:
The maximum java heap memory (set to 4 Gb by default), let’s call it maxheap.
The available graphics memory (VRAM, video ram). It depends on your graphics card. Let’s call it VRAM.
The draw distance setting ,
.The maximum number of loaded stars,
. This is in the configuration file ($GS_CONFIG/global.properties
) under the keyscene.octree.maxstars
. The default value balances the maximum heap memory space and the default data set.
So basically, a low OutOfMemoryError
. To mitigate that, one can also increase the maximum heap space.
Finally, there is the maximum number of loaded stars,
Draw distance, minimum visual solid angle for octants to be rendered
Maximum number of stars in memory at a given time