3D modelling is the starting point for a high quality Augmented Reality (AR) experience. You need to create and tune 3D models according to a few key criteria:
- Good quality materials, and
- Realistic rendering
Time taken to load a 3D model is crucial for great user experience. Facebook AR Studio restricts effects to less than 2 MB.
A 3D model is a geometric representation of an object and is composed of polynomials (typically triangles or quadriterals). A low-poly 3D model has a low number of polynomials, will be smaller in size and hence faster to load.
There is a trade-off though. A 3D model with too few polynomials can show sharp edges or miss out important detail. Thus, 3D models need to be small enough to ensure good performance while still retaining important detail.
In 3D modelling terminology, a Material is the skin of 3D models and defines how 3D models look. A material consists of several parts.
The basic color and texture of the material is called Diffuse. The object can be opaque or transparent.
The material has a part called Specular that defines how the object behaves with light. This can affect whether we see the object as soft or hard. A hard billiards ball behaves very differently compared to a soft teddy bear.
An object can contain fine detail such as abrasions or veins like in a wood panel. A Normal map can display these details very effectively without increasing the size of the 3D model much.
Finally, reflections are a very important part of the user experience. Realistic reflections make an object pop and create a great user experience.
Lastly, getting a realistic rendering of the product requires fine tuning. From the amount of reflection to the intensity of lighting in a scene, fine and detailed tuning is necessary to create realistic representation of the 3D model.
3D Modelling for Augmented Reality
Let us consider a vase. The high-poly model contains 80000 polynomials and is 5.3 MB in size.
The same vase has been modelled with just 250 polynomials and having a size of 33 KB. The first image shows the low-poly vase. The second image is the same vase with a normal map. The final image has the normal map as well as a specular map.
3D modelling artists pay a lot attention to detail in order to create amazing 3D models. 3D models tuned for AR must be low-poly with high quality materials and result in realistic representations.