If you don’t see your model, try scaling it down. OBJ model vertices commonly have large unit scales in comparison to A-Frame, which uses a unit scale of meters.
If you don’t see textures on your model, try placing all .jpg images in the same directory. When an OBJ model uses multiple materials (.jpg images), make sure it defines object groups for the sub-objects that use each of those materials, so that Three.js’ OBJLoader can associate the materials correctly. It is tricky to work with model that has multiple layers of texture, or iridescent effect.
A-Frame’s loader component is not perfect, and you may find it difficult to load Collada files; OBJ files are often easier to work with.
You can find and download models on the web to drop into our scenes: