TilesRenderer: "ADD" seems to always load all child tiles

[manisandro]

Question

Hi

I'd like to write a plugin with a calculateTileViewError function which returns inView: false if the tile is farther away than a certain distance from the camera. As far as I can see in the current implementation [1], a plugin can only override inView to true, but not to false if the tile volume was above found to intersect the frustum.

Is it possible with the current plugin mechanism to implement hiding of far away tiles?

[1] https://github.com/NASA-AMMOS/3DTilesRendererJS/blob/master/src/three/renderer/TilesRenderer.js#L973

Supplemental Data

No response

Library Version

0.4.11

Three.js Version

0.170.0

[gkjohnson]

Hi @manisandro! This sounds similar to what @xawill and @jsulli were interested in (see #1116 and #1062), though I'm not sure if there's been any more work done in that direction. It's otherwise not supported at the moment.

What's your usecase in this specific instance, though? If you're just trying to modify the far plane for the camera used for traversal it would be much easier to just create a "dummy" camera that mirrors the positoni and settings of the real camera but with a different far plane.

[manisandro]

Thanks for your reply! My use case is the following: I have a with a 3D tiles model of a city. Especially in first-person-view mode, the performance is heavily affected by the fact that the frustum cone is horizontal an hence all tiles in the view direction will be loaded. Performance is even more affected when rotating the first-person camera, as it will mean that many new tiles from the camera point to the horizon will change their visibility. I've experimented, overwriting the calculateTileViewError function prototype, by clamping the visibility depending on the camera distance, and it brings a noticeable performance improvement. What I'd also like to experiment is setting that distance very close while rotating the camera, and then gradually increasing the distance while the scene is idle, as to gradually load the buildings from near to far.

[gkjohnson]

the performance is heavily affected by the fact that the frustum cone is horizontal an hence all tiles in the view direction will be loaded.

Generally this shouldn't be an issue if the tile set data is structured well assuming the performance bottleneck is the number of tiles loaded and rendered in a frame. If you can share the tile set I can take a quick look at the structure.

What I'd also like to experiment is setting that distance very close while rotating the camera, and then gradually increasing the distance while the scene is idle, as to gradually load the buildings from near to far.

Again this shouldn't be necessary if the data source is well formed but if you'd still like to try it I recommend passing a dummy camera with your modified camera settings into the TilesRenderer instead of using the main camera.

[manisandro]

The tileset is at [1], to see it in action see [2] (note that initial loading might be very slow if you are in a region for which the CDN has not yet cached the data, but once loaded, subsequent performance should be good). Thanks!

• [1] https://data.sourcepole.com/3dtiles/stadt-zuerich/tileset.json
• [2] https://qwc2.sourcepole.ch/?c=2652685%2C1189401&s=1000000&l=Buildings&bl=ch.swisstopo.pixelkarte-farbe&t=zh_1&v=3d&bl3d=ch.swisstopo.swissimage&v3d=2683202.9%2C1241426.1%2C6512.8%2C2683810.1%2C1246400.6%2C0.0%2C0.0

[gkjohnson]

Thank you for the link to the tile set. It looks like this tile set is fairly flat and using the "ADD" refinement at the root of the hierarchy, which is correct. This project hasn't been tested with many "ADD" refinement tile sets, though, since there haven't been that many available to test with and it looks like there may need to be some changes to this project to support ADD correctly.

It may be a few weeks before I can look into this but in the mean time I recommend using a "dummy" camera and setting the far plane to a shorter value.

[manisandro]

Ok thanks! Do you have some pointers re. setting the dummy camera which I can look at?

[gkjohnson]

// create a dummy camera with the adjust near plane
const dummyCamera = camera.clone();
dummyCamera.near = 1000;
dummyCamera.updateProjectionMatrix();

tiles.setCamera( dummyCamera );

// ...

// update the dummy camera position to match the render camera before updating tiles
dummyCamera.position.copy( camera.position );
dummyCamera.rotation.copy( camera.rotation );
dummyCamera.updateMatrixWorld();

tiles.update();

[manisandro]

Thanks a lot!