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It is also important to say that photos are the base for all kind of CG work. References are the most important thing ! BUT we do NOT try to reproduce the reality in CG because most of the the time it is boring. We propose an enhanced version of the reality and we arrange things in the picture to tell a story. Think of it like this : reality versus a perception of reality. Sometimes, realism needs a little push even if it is not in the reference.
I guess the studio where I felt most connected to History of Art has been Animal Logic. Which is crazy because the sequence I did on Lego Batman did not have any color key. At first I would not have believed it. It was so different to what I had been used to ! But Craig and Grant actually developed a very clever process which solves many issues.
So cool ! It was like a museum for the nerd ! I remember that Grant even had some shoes made out of Lego sitting in a corner. Where did he get that from ? Anyway, it is the lighting launch.
On Lego Batman we had to setup a sequence where Batman had mixed feelings. How do you translate that in lighting ? Grant imagined some clouds passing by and covering the key to alternate shadow and light. Brilliant. He used the final sequence of Akira as a reference.
Ideally, establishing shots would be the same between different departments : from the art department to compositing, so the master shots are always prioritized and finished first. But production reality makes this kind of plan almost impossible.
If the animation department starts close-up first and if production wants to make quotas at any cost, it will make things very complicated. One workflow makes the anticipation really interesting : when lighting starts right after Rough Layout (RLO). I have done this on Playmobil and it was a really good idea. Why lighting should be the last process ?
When an artist asks for my help to check his light rig, I ALWAYS end up removing stuff. For some reason, people think light rigs have to be complex. ON THE CONTRARY ! It does not have to be complicated, especially in a PBR setup with Global Illumination (GI).
Why that ? For a very simple reason : Let the render engine do the work ! Do not go against it. Less work for you, more work for the computer ! Use its full potential by letting the lights bounce naturally. Let them bounce !
In PBR, we actually rely much more on the surfacing. If you have to adjust the specular, SSS or indirect contribution of your lights on every shot, it is a surfacing issue. I actually do not tweak many options on the lights when I work. Six of them generally give me plenty of control :
We did NOT have any parameters for spread, shadow color or indirect contribution. Why would you want a light not to cast shadows ? In PBR, that does not make sense. I agree that flexibility is important but keep in mind : would you rather tweak 60 shots or fix 1 asset ? I know that under a short deadline these options can come handy. But ideally, surfacing has to take care of these issues.
This panoramic render is the perfect way to approve your establishing lighting. It actually comes from the sequence described in the Types of shots section. It will allow you to check that all your lights are correctly calibrated and you did not forget any area.
Try to think about your light rig as a whole. Sometimes, when you create a light, you are just compensating for something that has been poorly done. And if you are missing some reflections in the eyes, it is maybe because your set is not properly lit.
Another technique is to render several shots using the same light rig to make it as universal as you can. There is no magical light rig that will cover 100% of shots. But refining the light rig on different angles is the best way to make sure your sequence will go smoothly.
You have to find the right balance between a flexible rig and an heavy rig that will be difficult to manipulate.The following three shots use the exact same light rig. It took me three weeks to set it up. Quite challenging !
I will quickly mention here that nailing a master lighting on several shots is a great way to setup a sequence. But it will not give you a proper cinematography. We will come back to that later.
Ideally, we should be able to test our light rigs on as many shots as we want without even opening Maya or Guerilla. On Playmobil, we would render First-Middle-Last (FML) of the whole sequence using a simple command line.
Place your lights like in the real world. Make it real, make it physical ! Place the practical lights physically where they should be. Think like a Director of Photography (DP). Otherwise it will just look weird. For practical lighting, you really do not have to complicate things :
On the next example, the sun is impacting the floor with a distant light. If I want to fake a bounce light from the impact, I will just place the area light at the same spot. Thanks to quadratic attenuation (decay), you only have to tweak color and exposure to make it look good. Easy.
Even further, we did NOT have blockers nor light-linking on Apes. We used CG black flags, like in a real movie set. Below is a photo from the set of Ida (Director : Paweł Pawlikowski, Cinematography by Lukasz Zal and Ryszard Lenczewski) where you can see the use of black flags.
I understand the whole mimic reality logic but it can make the work of the artists really difficult. They probably want the lighting TDs to think like Directors of Photography rather than just throwing lights anywhere they want.
Anyway you have to find a good balance on how much control you want to give to the artists and how many options you have in your software. This is why I use the example of Glimpse quite often : it had very few options but enough control to make it look good. I never felt limited with Glimpse.
Have you noticed how light is softened behind these big translucent sheets ? They pretty much look like Area Lights, right ? Think BIG. Having big lights outside of your camera field of view will help for :
Work your lights separately and be sure of what they do. Each light should have its very unique contribution. When I see artists ONLY working with all their lights on, I always wonder how can they know which light is doing what. Test them ONE BY ONE !
Here is an example of Light Path Expression (LPE) from Guerilla Render. It is very easy to setup and helps you lot to design your light rig. The following setup will be detailed at the bottom of this article.
If you are working on a daylight setup, try turning on all your lights except your sun. It should then look like a cloudy day. If not, keep working ! Since the sun is going to blast everything, it is a very good way to check if the light rig is well balanced.
We want to fix all the technical issues like noise and render times before propagating. But quite often tight schedules will make you propagate the light rig before you actually want to. This is why anticipation is so important. And as a supervisor you have to tell Production what is possible or not.
Many people thinks the more lights they use, the longer the render time will be. It is not entirely true. With adaptive sampling it helps to add a couple of lights to make the direct lighting more uniform. It will globally increase the luminance which means residual noise from other lights will be diminished and less samples will be overall needed.
There is nothing more dangerous than renaming stuff (object, lights, passes). This is why it is really important to think ahead. So many automatizations are name-based. You really want to nail this. Which light is your key ? Is there a naming convention to respect ? Can you use patterns (or expressions) ? After giving much thought, here is a convention I have created with the help of artists from Animal Logic and On Animation.
But when the look is approved, you need to do a pass of cleaning before passing it to the team. Just delete everything that is useless. And rename your lights according to their roles. You will also need to make sure that the rig is still working after the cleaning pass !
Deep is an image that stores depth values per pixel. The depth data is used by the deep merge to figure out which pixel goes in front of which. In my experience, this works for most situations but not always. It really depends on the amount of depth of field and the distance between objects.
Deep compositing can be quite useful as it completely removes the need for hold outs. The drawback to this technique is the weight of each frame because of all the data stored. This makes it impossible for some budgets and it can make your compositing software much slower.
On Apes, we had 3d motion blur and deep compositing. We would render a bunch of characters per layer (those apes were heavy in memory !) and the set separately. Less layers, no matte issue thanks to deep. Depth-of-field was done in Nuke to match plate. More efficient.
I am just going to mention it quickly since I have never used it personally. But there is a possibility in deep layering to use Camera Clipping. Rather than separating CHARS, SETS and PROPS which can be time-consuming, Camera Clipping allows to split in FG, MG and BG quickly. Using a distance with a few pixels margin may be a safe way too.
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