|
Page 1 of 15
Films made today are using visual effects increasingly. Some movies, like Transformers, have obvious visual effects and there are other movies (Fight Club, Panic Room)
where the effects are very subtle and , to the delight of the CG
supervisor, go unnoticed. This article
will attempt to cover some of the things to look out for when trying to
integrate computer graphics (CG) elements on to live footage. The two things
heard most commonly in this regard are lighting and texturing. Indeed, these
are quite important but, as you will read, there is a bit more to ensure a good
composite. I strongly suggest looking up images on the Internet to understand
certain concepts. For all practical
purposes, this is a crash course as some of the material mentioned briefly here
has been expanded into books by highly regarded artists. I will cover the following topics: - 1. Lighting
- 2. Shadows
- 3. Light Reflection
- 4. Light Refraction
- 5. Texturing
- 6. Signs of Age
- 7. Camera Calibration
- 8. Footage/Stock
- 9. Colour Matching
- 10. Light
Wrap
- 11. Motion
Blur Matching
- 12. Atmospheric
Effects
- 13. Environment
Interaction
- 14. Matching
the Animation
The numbering is not in order of priority. The following
will repeated later: If one aspect of integration fails, the whole shot fails. Keep in mind that the goal of your rendered image should be
to match the live plate as closely as possible. It is virtually impossible to
take out a render from a 3D package which matches perfectly with the live
plate. CG renders should be such that compositors can play with them to get the
desired result. The first step towards creating photorealistic CG is to
understand the concept of render passes. Virtually every 3D package has a
unique method of establishing render passes. Before moving on, do understand
how render passes work in your 3D application of choice. As said earlier, to
get a good integration everything (discussed below) needs to work flawlessly, a
single mistake can ruin the integration. A lay person might not be able to tell
exactly what’s wrong with an image, but reality is something everyone is well
tuned to. Although some of the things I
will write about are obvious, it’s best to cover all avenues.
|
