The Secrets Behind Realistic 3D Models in Movies

How do they make CGI look so real? A lot of work goes into the computer power and very advanced programs. At its core, CGI is simply instructing a computer on how to draw an image. This process requires meticulous attention to detail, often involving months of programming just to create the fur and hair effects in a single film.

From Basic Outline to Realism

The creation of a 3D model begins with the basic outline of the image. Then, to make the image look both 3D and realistic, it needs to have a "skin" or fancy shading. This can include various textures, shading techniques, and lighting effects to bring the model to life. Pixar, for example, took months to create the fur and hair effects in Monsters Inc..

The Role of Research and Modeling

One of the most critical aspects of creating realistic 3D models is the research and modeling that the artists do to ensure that the movement, especially of animals and people, looks right. This can involve creating as many as 30 images for each second of video time. New programs can now take a start image and an end image and create all the in-between images, but this still requires a significant amount of computer calculations.

Realism in CGI

Recreating actors and their performances is one of the hardest things to do in CGI, and it is usually only done when there is no other option. CGI isn't just about animating stuff; it uses 3D viewing models. For instance, when animating living creatures, technicians might use blue costumes with white balls to record actions, making the action animation part easy. Other animations will be done through beveling and shadowing processes.

Texturing, Shading, and Lighting

The texturing, shading, and lighting are more critical than the modeling itself. With the right maps and lights, you can make a sphere look like a realistic orange. Low-poly models can have faces mapped onto them and still do a credible job. However, using vector displacement mapping or encoding the modeling in another way can be considered cheating.

The Role of 3D Scanning and Photogrammetry

For absolute realism, 3D scanning or photogrammetry is often used. If you want an image to be photorealistic, it is best to take a picture or scan the 3D model. High-end studios use 3D scan data to record BSSRDF curves for shaders and capture lighting by using reflection maps from regular cameras or 360-degree HDRI scanners. This helps eliminate as much guesswork as possible in creating photorealistic shots, especially when integrating 3D with filmed material.

The Role of High-End Scanners

For sets, high-end LIDAR scanners also provide a realistic 3D base. HDRI probes can be used to capture lighting conditions, making it easier to replicate the exact lighting in the scene. This level of detail and precision is crucial for creating lifelike and believable 3D models in movies.