It’s Green

The Enterprise gets her base coat of paint, and it’s green.

USS Enterprise WIP #0010 – 9 July 2019 (673 KB, 3840 x 2160)

As mentioned in my previous post, I’ve been evaluating OTOY OctaneRender, a GPU rendering engine that leverages the power of modern graphics processor units to generate images in seconds and minutes, instead of the minutes and hours required with traditional CPU engines. I started my subscription last Friday, and as I learn OR’s capabilities, quirks, and limitations, I am beginning to realize that in some fundamental ways it’s like learning how to model and visualize all over again. Nonetheless, I can tell that it’s the best $20 (a month) I’ve ever spent on this hobby of mine, if for no other reason than the fact that I can toy with some settings, hit a button, and see the results of my adjustments instantly, vs. having to wait for a CPU-based render engine to grind out the pixels at a comparative snail’s pace.

Over the past couple of evenings I’ve been experimenting with the different surface materials available in OctaneRender, trying to find a “base coat” that closely emulates the green-tinted surface of the original eleven-foot studio model of the Enterprise (click here to see a photo of the model during its recent conservation by the Smithsonian Museum). One of the goals I have for this project is to create a model that uses “real world” materials (or as close to “real world” as one can get with a fictional starship from 226 years in the future), so I’ve been looking closely at OctaneRender’s “Universal Material”, OTOY’s implementation of PBR (Physically Based Rendering, a surface shading methodology that’s supposed to more accurately emulate how light bounces off of, reflects, and refracts with surfaces).

What you see here is about as close as I’ve been able to get. What I like about this material is that the green tint is derived from the index of refraction (IOR) of the coating material applied to the base layer, so in that sense it is a “realistic” surface with real-world properties. Where reality starts to mix with fantasy is the base layer: the coating is applied over a futuristic 20-80 mixture of OctaneRender’s “Metallic” and “Glossy” materials, which serves as the outer skin of the Enterprise. (In my imagination, the Enterprise hull is a futuristic blend of metal and ceramics;  a.k.a. unobtainium.) I also like the fact that the tint is only visible when looking at the surface from mostly perpendicular angles to the light source, so the Enterprise won’t always be green. And what’s really neat about this base layer is that its inherent iridescence opens up all kinds of interesting possibilities, including emulation of the pearlescent effect the refit Enterprise sported in Star Trek: The Motion Picture.

So now that I’ve settled on a base coat of paint, I can dive in to the nitty-gritty of texturing with OctaneRender, and this is where the aforementioned learning really starts. With traditional CPU-rendered models, I would start working with texture maps (images that are “projected” onto a surface to emulate dirt, scratches, changes in color, etc.) to “dirty up” the base surface of the model so that it doesn’t look so plasticky. Although I could also do that in OctaneRender, the base philosophy with GPU rendering is speed, speed, and more speed, and loading image bitmaps into the limited memory of a GPU goes against that philosophy. So, I’m going to (as much as possible) try to limit myself to the procedural textures available in OctaneRender, which only minimally impact GPU memory and render times. After all, if I loaded up the model with traditional image map-based textures, the slowdown in rendering speed would negate most of the reason for using the GPU in the first place. Stay tuned…