... Cinema Lens
Cinema Lens is an image I created for this very website. I wanted an image representing DSLR Cinematography and simply couldn't find a suitable one I was allowed to use.
Quickly the idea was born to create one myself... in 3D.
For modeling I nearly always go into Softimage as I find its modeling tools a lot more intuitiv and convenient than the ones from some other software packages.
Nearly every project starts with some internet search of images that could be used as reference. I found an image of a Zeiss CP.2 lens (most likely the 15 mm/T2.9) cut in half and thought it would make for a good reference.
A cylindrical object is fairly easy to build even if it is as detailed as a lens. It basically just involves drawing a bunch of curves, rotating them around an axis and let the computer generate geometry from the resulting rotational curve.
Et voilà, a cylindrical shape!
Since this image should not just show an object but a cut through of a lens it was necessary to model the interior brackets,gears and the glas elements that make up an actual lens. The cutting surface is the most important surface on this object and it had to be closed with proper edgeflow to ensure nice shading later on.
Once modeling is finished the UVs need to get layed out so textures have a place to sit on.
I experimented with several layout methods, mostly automatic methods in Softimage to speed up the process. Since that didn't work for me I tried PTex. Now PTex is a whole other game and comes with it's own set of problems.
I created a PTex texture in Mari and tested it in Maya with VRay. At first glance it worked fine but it had it's issues with geometry smoothing on rendertime. Since I chose to use less dense geometry and therefore rely on VRays subdivision attribute to smooth my geometry on rendertime
it turned out PTex was not the way to go. In the end I decided to do it like I do it most of the times anyway... A proper relaxed object specific UV layout in Headus UV Layout. For close up shots I usually go for a multi patch uv layout as it allows me to stick with 2k textures rather than using 4k or 8k images that would only slow down the texturing process.
Since the cutting edge is the most important surface on this object I wanted to have more texture resolution for it than for the other surfaces and so I scaled up their UVs.
Scaling UVs can of course introduce a whole bunch of other problems like inconsistancy of scaling resulting in a different look of a material from object to object. At first I thought I had to make sure the scaling was based on a numeric value rather than by hand with Mayas scaling tool but I soon realised that this was not the only thing I had to consider.
As it turned out Headus UV Layout gives you a consistant scaling of UVs within an object but not across several objects.
To ensure the consistancy of UV space across multiple objects I kept the scaling at 1:1 from UV Layout and scaled afterwards in Maya. This way I could make sure the UV size matched across all objects where needed. Since I did a lot by hand it was no longer 100% accurate
but that was a trade off I made gladly to gain a higher texture resolution that would hold up similarily when projecting onto the geometry later in Mari.
It did mean a lot of UV manipulation and tweaking by hand. As the results show however, it was worth the effort.
Texturing looked like a fairly easy process in this project. The only textures I was going to use was a brushed metal texture I created in Photoshop as a 4k map and project it onto the surface.
I thought about creating the decals in Mari using the masking tools and triplanar projections to create icons for T-stops and focal distance but then decided against it. I modeled the icons instead and placed them to their appropriate position.
All in all texturing was not a big deal as the lens should look like it was brand new, cut open at the factory and therefore had no dents, scratches or dirt.
Modeling done, UVs set and textures prepared... now it's time for shading and developing the look of the materials in order to make it look as desired. Lighting and rendering I like doing in Maya with VRay or Arnold.
In this case I chose VRay as I had a shader library already in place and didn't have to create all shaders from scratch. Most shaders I use come from my shader library I created way earlier in my spare time.
Some materials I need to create from scratch since a library is never complete. With a basic light setup I can start rendering and check for issues I might have to address.
As it turned out the "Brushed Metal" textures from Mari were all fine and good but in order to adjust the look more easily
I decided to not use the textures from Mari but project a texture in Maya that would show the brushed metal. This way I had way more freedom to adjust the look as desired.
The image above shows the initial material setup and the first issues.
The images above show some testrenders with different shader settings, left image being the most recent. The differences can really only be seen clearly when looking at the full resolution.
To the right a more artistic approach of the multi layer lens coating effect modern professional lenses all have in common.
To the left a much more pleasing look based on real world physics interpreted in an artistic way. I had to cheat here as VRay does not offer the option to calculate wavelength reflections based on coating thicknes in nm.
Also it is hard to get your hands on the info which combination of materials and their thickness manufacturers use for their coatings and in which order to cancel out specific wavelength reflections that then result in the colors we see in lense coatings. I know this is quite a mouth full and to be honest quite sophisticated physics going on with optics that you have to get your hear around to understand and replicate the effect believably.
As soon as I was happy with the results it was time for the next step.
Now that the previous steps were all set and done, all erros fixed, I could start lighting the scene properly so it looks not just lit but aesthetically pleasing. In this case the render setup was fairly easy. I managed to render without renderlayers and without object properties but with a bunch of renderelements.
This approach is not overly compositing friendly as it does limit the options of adjusting position and elements seperatelly. As I was my own client and was happy with what I had there was no need to go the extra mile so I went with this workflow.
Although I nearly always prepare a scene ready for animation I chose to do a still in this case. I thought about doing an animation but quickly let go of the idea when I saw the rendertimes. Those did have a big impact due to the very blurry reflections, multiple objects refracting and reflecting each other and the texture size used. The final image size of 5170x2248 pixesl did not help in reducing the rendertime either.
No job is finished until the paperwork is done or in CG terms until the image has seen some compositing. In this case I tweaked the 3D render so far as there was not much I wanted to do in Nuke which is the compositing software of my choice when it comes to treating 3D renderings. I basically just enhanced the contrast, added a slight glow and added a green reflection to the front lens element.
I don't like using Photoshop for compositing as it is incapable of doing a proper beauty rebuild in 16bit. It needs to be in 32bit mode to do so but then Photoshop only offers a resticted selection of tools that make it feel kind of crippled. I use Photoshop for retouching photos and creating textures only.
Final composite with wireframe blend
This concludes the making of "Cinema Lens". I hope you found it interesting