What is 3D CGI?
To keep things simple this explanation is framed in terms of creating 3D images of jewellery.
3D images (also called 3D renders or 3D visualisations) are computer generated images (CGI) made using a 3D modelling program in conjunction with a 3D rendering application.
The 4 step process to make a 3D image of a piece of jewellery is:
Make a model
Add materials to the model
Light the model
Render the image
1. Modelling
Modelling starts with a polygon - a rectangle made up of 4 points connected by 4 edges - which is then connected to other polygons which are in turn manipulated to make any shape required - kind of like chicken wire used for sculpting.
The below images show the various phases of modelling a ring - click to enlarge.
2. Materials
3D materials are designed to replicate real world materials and they are made by inputting different parameters that include colour, specularity, transparency, roughness, solidness, flexibility, etc.
A combination of these parameters in varying amounts means that any material can made to replicate the characteristics of a real world material.
In the below image, I've used red for the ‘platinum material’ and blue for the ‘diamond material’ for easy visualisation purposes.
3. Lighting
The model and materials are nothing without light and the lights in the rendering application are based on real world film and photography lights.
This is my favourite part of the 3D process as I have been lighting jewellery in a real world photo studio for a number of years and have a good underpinning knowledge of how light behaves in conjunction with shiny precious metals and translucent coloured gems.
Below is an image of the 3D space with a model of a ring placed on a surface and surrounded by a lighting set-up.
4. Rendering
Rendering is another word for processing and is the final 3D stage whereby all of the parameters that have been applied to the model, materials and lighting are processed along with the final output details such as image size, dpi, colour space and LUT’s etc.
The below image shows the light and camera set up on the right with the render-in-progress on the left.
5. Final Image
The final render/image/visualisation needs a little jiggery pokery in Photoshop, not least because (again as in the real world) shiny precious metals and translucent precious gems require different lighting set-ups and therefore composting skills are required.
Final image below and a very simplistic breakdown of the 3D image making process above.
