Glass Design using C4D Caustics

Caustics are light rays emanating from a point and reflected by a curved surface.

Before Cinema 4D, I would have added light effects in post production as a fail-safe approach to add drama to an image. To do that, I would have resorted to Photoshop. In this example however, I went for a different approach. I added the light effects straight into Cinema 4D which gave me a more natural looking visual. The trick here is really in the Cinema 4D render settings which allow for a powerful C4D caustics generation. I first learned about caustics in Cinema from Greyscale Gorilla’s video tutorial which you can watch on his blog.

After watching the tutorial, I thought I should try rending caustics with a transparent 3D model in Cinema. I had a model of Kidrobot’s Dunny at hand and started experimenting. I soon realized that the more photos I add, the greater the intensity of the light emission. This also makes for slower (much slower) render times, but it’s worth the wait. The final render settings for this glass Dunny are as follows:

• Surface Caustics enabled  with strength of 4100 %. I also used two spot lights to light the scene. Each of these lights’ photons settings were set to high values of 100% energy and to 3000000 photons with surface caustics enabled.

Post production

After the render was complete using C4D caustics, the image needed a bit of polishing. I rendered the Dunny with an object buffer which gave me an easy way to make a precise selection. I then used different images I found on the web to add a background texture as well as a few addition light streaks. I used the Screen transparency mode on these light streaks to make them look as if they are either inside the glass body or emerging from it. The final touch was to color balance the image with a Photoshop adjustment layer to make the artwork come together. I used the artwork as my Twitter background.

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