I worked with April Boardman of Redhead Design to complete an extremely difficult retouching job for JW Marriott. By approaching it as a 3D modeling and rendering project rather than a retouching project, it took less time to complete and the resulting image looked more realistic.
The client provided a photograph of a wall sculpture that they wanted to use for a holiday card, but requested that the black arms be changed to silver, the background be changed to black, and all the jewels sparkle and refract light into bits of colors of the rainbow.
Approached solely as a retouching job in Photoshop, the following difficulties arose: 1) Shifting the color of a black object to silver is possible, but the black arms of this sculpture had little detail in the shadows with which to work; 2) Changing the background to black would require constructing a time-consuming mask or clipping path in, out, and around all 108 arm/jewel pieces. Even then, the light cream background of the photograph would still show through every jewel; 3) The time required for painting and faking the sparkle and rainbow effect in a jewel would be multiplied 108 times!
Having skills in 3D modeling and rendering, I realized that these challenges would be more easily met by quickly reconstructing the wall sculpture in Cinema 4D, a 3D modeling and rendering program. Once the model was constructed, changing the colors of the objects, adjusting the lights to create sparkle, and simulating the refractive rainbow effect would be a breeze! Plus, there was no time-consuming fudging of the positioning and patterning of the reflections and refractions of light in Photoshop; all the paths of light are calculated by Cinema 4D to be physically accurate. Once everything is set up properly, just click a button!
The modeling of the sculpture was as simple as constructing one arm/jewel piece and then repeating it in a pattern that matched the original wall sculpture. Each arm consisted of a simple cylinder for the stem with a ring attached to it that frames the jewel. I already had the 3D model of the jewel that I had created for another project.
Cinema 4D has a feature for repeating objects called the cloner object. I assigned my single arm model to a cloner object and specified how many times to repeat the arm and to repeat it radially. Each ring of arms has its own cloner object and the rings near the center have fewer repetitions specified to match the original sculpture.
Another feature of Cinema 4D is the ability to break the perfect geometry of a mathematical environment by adding subtle random variation. By assigning Cinema 4D’s random effector to the arms, I recreated the slight variation in position of each arm that can be seen in the original photograph of the wall sculpture.
In the physical world, the colored bits of light the client wanted to see in the jewels are a result of the same bending or refraction of light that happens when light goes through a prism. The actual breaking up of the light into a rainbow of colors is called spectral dispersion. A jewel acts like a prism, but multiplied many times over. Cinema 4D can bend light but it cannot physically simulate breaking it up into the rainbow of colors. Fortunately, I had already learned a workaround method of simulating that.
The rainbow effect occurs when light passes through a prism because differently colored light rays bend at different angles as they are refracted. To simulate this in Cinema 4D, I rendered three separate renderings of the wall sculpture: A green rendering where the glass bent the light normally; a red rendering where I set the glass to bend the light a little more than normal, and; a blue rendering where I set the glass to bend the light a little less than normal. Then, I opened them in Photoshop and layered them on top of one another to create a full color image with a simulation of spectral dispersion.