The model is awesome and I constantly use it in my tests and experiments.
But the scale somewhat surprises me.
The plane is modelled at scale of 22×29×10 units, which is kinda huge in meters for a real plane (compared to a Cessna of 8×10×3 meters)
However, it is scaled down in Rootnode.0 by 0.01 to the size 0.22×0.292×0.106 units.
But why?
It is like Babylonjs works better with models within 1 unit or something?
Maybe @PatrickRyan knows some good practice with units usage between different DCC and Babylon?
@qwiglydee, there is a bit of context which may help explain things here. This model is a remnant of the 3D for Everyone initiative that grew into Remix 3D, Microsoft’s asset library for use in Paint 3D. These models were created by a team at Microsoft in Maya, which uses a base unit of cm. So it was likely intended to be 22 x 29 x 10 cm when authored, or about the size of a toy plane. Since glTF does not specify a default scale, the renderer will use its default scale which in Babylon’s case is meters. The renderer will just see 22 x 29 x 10 units which in Babylon’s case would mean 22 x 29 x 10 meters. These assets were modeled almost 10 years ago but since we had access to them, we decided to use some of them as example models due to the models having some features we wanted to highlight like skinned animation.
So, the scale on the root node is intended to get it back to its original size as authored and keep the camera within a reasonable distance from a model at that size. Babylon could easily handle a model at life size for a plane, though the camera would have to be adjusted accordingly as well as the near and far clip planes to make sure we aren’t packing in precision we don’t need at the expense of the far clip plane.
There are no hard and fast rules to follow when it comes to scale coming out of your DCC tool for Babylon. You certainly want to balance texel density with scale (in for form of X texels per square meter for example) to keep all of your assets looking the same in terms of resolution. You may also want to use a specific scale based on physics calculations or for view distance within your art pipeline. If Blender’s UI is set up for meters and Maya is set up for centimeters by default, the cameras will be tuned to those distances and using the same camera settings in Maya with meters will result in artifacts on screen. This means the art pipeline will either need to be balanced around one unit or your scene may need to accommodate a smaller unit. Or you can use the ambiguity of units in glTF to your advantage. If your art team wants to keep their DCC tool in cm, but build everything as it would be scaled in real life (8 x 10 x 3 cm for your cessna example) importing it into Babylon will result in a plane at life size. I hope this makes sense but feel free to ping with additional questions.