How do babylon demos seem to have very small file sizes

[steverob]

In the process of building something with ThreeJS. When trying to find stock models for us with our WebVR project, most of them (especially office or apartment interior models - obj files) seem to be really huge and we do not want to use them for this web project.

But, BabylonJS seems to have some demos which are rather rich, yet the model sizes are under 15MB mostly. Like this one for instance - http://www.babylonjs.com/demos/retail/

Absolute Newbie to webGL and 3D modeling in general. If we want an apartment or office interior model, and we want to optimize for file download size for our users via browser, what sort of formats should we look for and are there special settings that need to be made when designing the models themselves to yield them in a light weight manner for web use?

Appreciate some gyaan here. 

[Nesh108]

Hey @steverob, that's because normally the heaviest stuff in a 3D application is all the mesh data. OBJ is often used as it's a common format but it can be pretty heavy. On the other hand, Babylonjs also supports its own format (.babylon), which is basically a very light textfile (instead of being a binary) containing all the instructions on how to build your meshes.

In that demo, the meshes 'Retail.babylon' is 13.4MB while the rest is pretty much textures, the code itself and the babylon library.

ADDITION: For your second question, if you are using Babylonjs, make sure to export to the babylon format (https://doc.babylonjs.com/exporters/blender) and to follow the usual techniques to decrease the size of a 3D mesh (https://i.materialise.com/blog/reduce-the-file-size-of-stl-and-obj-3d-models/).