Additional blog posts.

These next blog posts are from another blog I had set up for The Ravens project, directed by Sophie Lodge. For some reason, I thought I had to have seperate blogs for each film, which is silly now that I think about it. So he are the blog posts that I have done.

Tracking (done in december)

During the first term, I was down to work with the following groups: The Deep, Unhatched and Patience. This has now changed; the Patience group have decided they will do the lighting themselves so I will no longer be working with this group. But I have spoken to Sophie Lodge, project leader on a documentary project called The Ravens. This will be a compositing project, mixing 3D with film footage. This is a great opportunity to work as a lighter because it is matching the lighting from maya with the film footage. This is an area I am really interested in and this is where I would like to end up as a job. Sophie has sent me a lighting plate for me to work with. It hasn’t been tracked, but I don’t mind this at all because I really enjoy tracking. The tracking will be done with MatchMover. This is a playblast from an automatic track done in MatchMover and then exported in to Maya: I’ve decided to do tracking with Match Mover on my mac, A consistent problem that I have been having is when ever I import the image sequence for tracking part of the video window goes grey which makes the software unusable. I did some research online and it is to do with the nvidia graphics cards installed on the macs (http://usa.autodesk.com/adsk/servlet…linkID=9242258). What I will do is just use maya live and do all the tracking through that. If this proves to be too difficult then I will use MatchMover on my PC. An advantage of me using Maya Live is that I’m more familiar with it compared to MatchMover.

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Sub Surface Scattering Research.

I research sub surface scattering (SSS) online and SSS is the translucency of an object, or the amount of light that is allowed to pass through the object.

In Maya two main kinds of SSS shaders one can be used for inanimate objects such as plastic and wax and then there’s the misss fast_skin_maya, this shader has a considerably more amount of controls on than the standard SSS shader. Such as: epidermal, sub dermal colours; these are used to imitate the different layers of your skin.

The SSS shaders took me a couple of days to get my head around. What was helpful was to watch the videos several times, taking notes and implementing it myself during the tutorial, this took long time, but I am glad I did this because I have a better understanding because of this.

After I got a better grasp of the Sub Surface Scattering skin shader, I applied the material to the basic rig character who is in the previous Pontoon test renders. A problem that I have come across is that if I set up some standard Maya lights, the SSS shader comes out quite nicely, however when the shader is put in the same scene as the physical sun and sky light system, the SSS shader is rendered horribly.

Please see render below to see what I have been writing about.

A rendered image of the “MI Sub Surface Scattering” shader not working well with the “Physical Sun and Sky”.

So after I came across this I entered the following search criteria in to Google; to see if there was a solution to this problem: “subsurface skin scattering not working with physical sun and sky”.

The problem was with the sub surface shader. By default the shader does not account for indirect lighting, which is what the physical sun and sky is.

This can be turned on by going in to the sub surface scattering shape node and turning on the “include indirect lighting”.

What you also need to do is uncheck the composite mode (under algorithm control) on the Sub Surface Shader itself. This will then allow the sub surface shader and the Physical Sun and Sky to work together.

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Raven Light Test #1.

Sophie went out on Sunday to take some test photos of a ball ball on a pavement to test the ball lighting technique and see it if is a viable option to go on to develop a work-flow when lighting each scene. Sophie asked what I thought and if I thought that they were too washed out. At this stage, I still didn’t really understand the technique nor what to look for. So my response was to use a reflective ball ball next time so that we can make a HDR image because Image Based Lighting is another technique we can use to light these scenes. It may also provide me with better lighting information, but again, I am not too sure what to look for. Here is one of the images that she took:

Light Test #1.

Due to the fact that compositing is not an area that I have researched thoroughly, I wasn’t confident in what I was meant to do with regards to setting up a plane for the shadows. The Physical Sun and Sky method was proving too complicated for what I wanted to do, especially when the image plane was causing interference with the lighting, I decided to stop there. So I decided to light the shot manually with Maya lights.

So I setup a 3 point light system in Maya (See image below) and plugged an image through a camera in Maya (select camera. View> Image Plane> import image). Upon reflection this method would have been the one to use when using the physical sun and sky option as apposed to creating a planar and applying an image sequence as a texture…something I should definitely bare in mind for the next light test.

During this lighting test, I have begun to understand more why the ball lighting technique is used, it’s used as a reference object in the scene, you can use it to see if there are any caustics that would be involved because I was asking myself this when I was lighting these scene, further more light direction, shadow direction, length and detail.

One of the main issues that I’ve come across in this test are shadows not coming up in the render. I turned off each light to see if any of the lights were overriding the key light, no result. I turned Maya on and off to see if it just needed resetting still no result. I have checked the render globals, ensured Raytracing is set as the renderer, I have increased the shadow samples as well. When this did not work I changed from raytrace shadows to depth map to see if that would make a difference, but this did not work.

Issues that have been sorted are attaching an image/image sequence through the camera as apposed to using a planar (this causes a shadow overcast on the object) and secondly not so much an issue, but a positive outcome from this test; I have a better understanding of why ball lighting is used. An issue that hasn’t been resolved as of yet are the shadows, this will be something that I will continue to test through trial and error and I would not be surprised if it was something simple.

What I have also researched for lighting and rendering for the Raven project, I would need to create a shadow light, so a light dedicated to just emitting shadows- so this would go on a separate layer. In addition a beauty pass, occlusion specular, highlights and maybe a lighting pass (I am referencing a book called: [Digital] Lighting and Rendering by Jeremy Birn).

With most of these renders, they can be done in one go using the render pass system which is quicker because it renders the image sequence but at the same time it breaks each image down in to those passes that you specify without incurring any additional render time. The occlusion will probably have to be rendered on a separate layer.

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Ravens Lighting Plates Analysis.

Sophie has sent me the lighting plates from the shoot and I have analysed two of the plates. Here are my analysis sheets:

Shot analyses and where I would place the lights if I were implementing a 3 point lighting scheme.

A birds eye view of the 3 point lighting scheme as seen in image above.

I broke down the shot regarding the light sources and then placed a 3 point lighting system in.

At first when it came to analysing the shot above, I was slightly confused as to where the sunlight was coming from. This is because the shadows are quite misleading when looking at this still image. I had to go back and watch the QuickTime file in order to determine what shadow belonged to which moving object. In addition one particular burn spot made think, is the sun high or low in the sky? But when diagnosing the shadows the answer was obvious- the sun would have been quite low in the sky when scene was shot.

Sophie contacted a friend who works in the CG industry, and a technique that he talked about was using “lighting balls”, you put these in the scene that you want to video and you can gather all your lighting information from there. This seemed like a weird but interesting method, and as it’s an industry standard, something worth looking in to, here’s what I found:

“It can be useful to shoot a chrome ball or grey ball in the background plate (as a separate take). The chrome ball will show you all the relevant light sources, both direct and bounce light. The grey ball will also show you lighting cues and is useful for 3D crew. They can put a 3D ball in next to it and adjust their lights until they match the real ball.”

And

“It’s also useful to shoot some wide shots of the general scene during a take to show the light sources and general stage setup. You may think you will remember details but weeks after the shoot it’s better to have a pictorial record”.

Researching these areas will help us use a process of elimination as to what method to use when lighting the scenes and will allow us to develop a work-flow for this project. Sophie will go up to London and do some more filming using the spheres so that we test and see if this is a viable option. What I will do as well is go up to london with her, and take some photos of the scene, this serves 2 fold- reference of the general scene to show the light sources and secondly to take some panoramic shots and make a HDR Image as there is a lighting method called Image Based lighting, which could potentially be used and perhaps reduce the amount of manual lighting involved. Further more using a reflective sphere will capture a fisheye view of the environment and we can use this as a HDR image.

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3 and 4 Point Lighting.

These are two processes that I researched earlier in first term, and I have found these two lighting methods to be incredibly useful for lighting scenes in The Deep and Patience (which I am no longer working with), it gives me some sort of base to work from in instead of placing lights anywhere. This also ensures there is some light falling on most areas of the subject, which I’m confident will be useful source of reference for all three films that I am going to be working on- The Deep, Unhatched and “The Raven Project”. So here’s the research that I have collected:

3 Point Lighting Diagram.

3 Point lighting. This is used in film, videos and photography, so widely used and certainly industry standard. I’ve been taught this on a product and advertising photography course by Ray Davenport and this research has helped reinforce what I learnt on the photography course.

Key light– this is your main source of light, so the light with the highest intensity. This is placed to the side of the subject so that there can be some shadow on the other side of the subject.

Fill light– this light is dimmer than the Key. Placed opposite to the key light (see above) and is used to fill the shadows created by the key light. A method that is used in real life (as apposed to on a computer) is to move the light further away from the subject, thereby softening the light.

Back light– Used to give the subject soft highlights and definition from the rear and to make the subject look 3D, and so that the subject is separated from the background

Following on from this, Ray Davenport taught me you have lighting ratios, this dictates how dark the shadows are. You can have: 2 to 1, 3 to 1 and can go up to 9 to 1 lighting, which dictates the intensity or how dark the shadows are on the subject to give the scene/photograph more atmosphere. 2 to 1 means there is 1 f stop between the Key and Fill lights. 3 to 1 means there is a 2 stop difference between the Key and fill lights.

4 Point Lighting Diagram.

4 point lighting has the three main lights just like 3 point lighting but the fourth light is aimed at the background, this provides a mixture of light and dark. “Four point lighting is supposed to be the practical basis for most narrative film lighting, so you have the options to change it”. Read more: http://www.brighthub.com/multimedia/video/articles/59485.aspx#ixzz1ASPDNNwC

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Groups Update.

During the first term, I was down to work with the following groups: The Deep, Unhatched and Patience. This has now changed; the Patience group have decided they will do the lighting themselves so I will no longer be working with this group. But I have spoken to Sophie Lodge, project leader on a documentary project called The Ravens. This will be a compositing project, mixing 3D with film footage. This is a great opportunity to work as a lighter because it is matching the lighting from maya with the film footage. This is an area I am really interested in and this is where I would like to end up as a job.

Sophie has sent me a lighting plate for me to work with. It hasn’t been tracked, but I don’t mind this at all because I really enjoy tracking. The tracking will be done with MatchMover.

I will update this blog with a couple of lighting tests for The Ravens. I intend to research Image Based Lighting and will be placing one or two photorealistic royalty free models in to the footage to see if the lighting works.

In addition I will break the scene down in order to see where the light sources are.

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Andy was after a turntable of the submarine underwater. This turntable is freeze frame from a scene in the film. The purpose of this was to get an idea of what the lighting would look like from different angles.

I rendered the scene out on different layers. Here is the link to see it on youtube: http://www.youtube.com/watch?v=ZACxaXMe5TM

Evaluation.

For this clip I had to make the bubbles in Maya instead of After Effects as the bubbles plugin (After Effects) is only 2D and therefore won’t work with this turntable. When organizing the render layers I placed the bubbles on a separate render layer, the problem with this was that the bubbles were visible when they shouldn’t have been, such as at these points in time: 0:26 and 0:35. In the future, for these clips I would have the bubbles on the same render layer as the submarine.

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