QGIS 3D view - WMTS layers slow to load

[qgib]

Author Name: Jeremy Palmer (@palmerj)
Original Redmine Issue: 17559

Redmine category:3d
Assignee: Martin Dobias

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I’m noticing that WMTS tiles take a lot longer to load in the 3D view than in the 2D map. In many cases refreshing the 3D map can take up to 30secs, when the 2D is less than 3secs. I believe the WMTS response time is not the issue...

[qgib]

Author Name: Jeremy Palmer (@palmerj)

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Comments from Martin Dobias:

I think I know why WMTS is slow in 3D view... the terrain tiles are processed in a queue serially, one tile at a time: 1. request WMTS data for the tile, 2. wait for reply, 3. repeat with another tile. This is obviously much slower than requesting all tiles at once and then waiting for the replies (that's how it is done in main canvas, because there is just one map extent to render). There should be some ways how to make the queue processing more parallel, but that is probably going to take longer more effort than a bug fix. If the WMTS tiles are already in the disk cache, their rendering should be relatively fast.