A 3D model is a digital representation of three dimensional (3D) object.
3D models are created in 3D Modelling software, there are many 3D software applications depending on the industry and what the 3D model is used for. Each software application has it's own 'native' format and usually can also export to more portable / universal formats. See [formats]
A 3D model is usually made up of
the 3D mesh of polygons
the materials of the model including texture images
any animation of the model
For Plattar, your 3D model needs to be made for 3D visualisation. This means it is built to run in the web browser or mobile app which requires
that the number of polygons is within a range
that the materials use textures below a certain size
Each scene can have many 3D models , but be careful that the scene downloads in a reasonable amount of time, and performs ok on your user’s devices.
3D models in Plattar use the gltf format. You can create/convert your models to this format by using the Creating a glTF guide.