Billboard + 3D model mixed?

Hello all,

We're quite happy that Cesium now supports 3D models, as it was, I
believe, one of the major items missing on the wish list we had to
replace a desktop product with it. We converted successfully our about
70+ 3D models to glTF.

I have a small question regarding our particular use case: we have
plenty of entities floating around the globe (vessels, aircraft,
people), and rendering them all using 3D models, would probably be an
overkill GPU-wise, but we're willing to try things out. We're
exploring the idea of

A) replacing them with billboards when the camera is distance enough, or,

B) alternatively, having the 3D model maintain a certain minimum screen size.

So, we'd kindly request any input or opinions on:

A) would there be an "easy way"(tm) to implement such an effect via
CZML production (i.e. A "minimum/maximum viewing distance" of sorts)
so that we could add both a Billboard and a Model to a CZML entry in
such a way that one would replace the other and transition back/forth
rather seamlessly?

B) is there a way to control a model's minimum scale/screen size so
that when one zooms out the model stays, at least, at x pixels across

Many thanks in advance for any input.

Hi Hugo,

For performance, I would go with (A), which AGI also does in our desktop products.

As for the implementation, we plan to implement “display conditions”, which are generic queries for when to display an object, e.g., based on distance to camera, camera altitude, time interval, etc. In the meantime, it would be pretty easy to set the show property based on the distance to the object.

Also, your app sounds exciting. Can you share any recent screenshots including the models with us?