Visual Development- an Unexpected Journey
This month in VSD we had 2 main lab projects, split over
multiple labs. The first was a lesson on lighting things accurately based on
reference and the second was about UV Layout, diffuse textures, generating
reflection/refraction/caustics with materials and render layers and
post-processing in Nuke. I’m going to be
going over these projects and the overall process of lighting, shading
networks/textures, and rendering in Maya, and compositing the render passes in
Nuke.
Project 1- Lighting
For the first project, we were given a rendered image of a
3d scene with a simple setup of two lights and we had to create our own lights
to match the reference as close as possible.
The version I came up with was close enough to the reference that if I
posted both of them, they would look like the same image. Here’s my version
below~
There are a few important things to consider when matching a
lighting reference. Firstly- Consider the light source. Where is the light
coming from? What is the physical source of the light? Is it coming from the
sun, sky, moon, an incandescent or fluorescent bulb? Even if you don’t know
exactly what the source of the light is, it would do some good to think
critically about what the source might be and determine what ‘feel’ you are
going for with each light you create.
This will make it easier when troubleshooting the position, intensity,
colour/temperature, or type of your light source.
This particular project had a directional light imitating
the sun in the front room and a spherical area light in the room in the back. The first image seems pretty dark as a render
because we were being introduced to linear workflow and we did not yet have the
proper gamma correction on our images for the final look. Working this dark was
a good way to get re-introduced to lighting because it isolated the lights from
the scene and gave a few, specific landmarks to hit for position and intensity
that would have been harder to follow when viewing linearly. The simplicity of the first project was
conducive to learning how to troubleshoot intensity, colour,
direction/position, and shadow softness.
In the second part of this project, we increased the
complexity of the lighting, keeping in mind the same basic concepts as before.
We started working linearly and had a second reference image to match. Again,
this is my image, and it was quite close to the reference, almost unnoticeably
so, with a little different noise and slight intensity difference on the portal
light-
This image brought about a few more things to think about.
There’s a lot more detail in this scene to match, so if our first portion of
the project was off, it would make more it difficult to match the scene. We had to create portal lights for the two
windows in the front room and for the room in the very back, casting
information from the IBL into the rooms- because otherwise it would have been
occluded by the room geometry and there would be no feeling of window light as
seen in the image. Portal lights are
quite render heavy, so it’s important to use them sparingly- only when you
really need them.
The light in the middle room went from a simple point light
to being a physically based, spherical area light with life-accurate
temperature settings. To do this, we created a Mental Ray physical light node
and plugged that into a black body light shader. This gave us a temperature
setting that can be referenced from real-world temperatures. Ranging from below
candlelight to sunlight and beyond, this option gives a great amount of
realistic control to the scene and allows for a good frame of reference for
what the light source “should” look like. This project also consisted of
troubleshooting final gathering settings for the noise/aliasing issues, and
raytracing settings for the bottle. The ray depth needs to be changed in the
render settings and on the material, so that that the glass can look like glass
(and not like some monstrous alien material that doesn’t obey physics).
The first scene was a good lesson in lighting, raytracing,
and final gathering, focusing on knowing how to control lights to act the way
we want them. Proper use of lighting can be the difference between a bland,
unimportant scene, and a soul-touching masterpiece so it’s important if you’re
using lights to know what you’re doing.
Project 2- Diffuse, Shaders, and Compositing
This project consisted of most of the month, and for good
reason. Each week focused on a different aspect of the project, from textures
to material building and finally compositing in Nuke. Here’s an image of the
project- I will go further into detail on that later.
In the first week we focused mostly on creating diffuse for
the project. We started by creating clean, working UV Layouts to make the
texture wrap around the object well. Without clean UVs the texture could be
warping or seams could be distracting, taking away from the realism of your
renders. The box was already done, so we had to choose either the gear or
scraper, or both, to set up UVs and textures for that object. I chose both,
because the two objects work differently, and therefore require separate
solutions for creating each. When given the option of either/or, I usually
choose both because I want to learn as much as possible about everything I do
so I know how to face any issue that comes my way.
We used photos of the models in the scene to make texture
maps for the diffuse colour. One part of creating textures that many people
overlook is the lighting of the photographs that they use. Every photo that you
use for textures has lighting information within it, and this information needs
to be muted for a clean looking render in Maya. I had to use many layers of
adjustments with masks to bring up the dark spots, bring down the blown out
bright spots, and adjust Hue/saturation of every part of the object to match
the rest. What you end up with basically
looks like a non-reflective, non-lit “skin” of whatever object you are
rendering, laid out cleanly on top of the UVs of the object.
It’s important to keep in mind exactly what each part of
your UVs represents, because if you don’t things can get confusing. I ran into
that issue when working on the gear notches. I had quickly aligned and
colour-corrected just about everything for the gear and when I applied the texture
to the 3d object, the gear notches were WAY off. I had forgotten two things-
one, I didn’t pay close attention to what the UVs represented in 3D space so I
didn’t properly align the photo with the UV screen shot; and two- I forgot
about the perspective of the image of the gear.
The side photo of the round object made the notches on the outside much
smaller than the ones toward the camera, and in my haste I overlooked this, so
I had to go back and manually fix each section one-by-one and subsequently,
seams had to be fixed again.
The next step was to add material attributes. We used the
mia_material_x Mental Ray material on our objects to create the scraper handle
and blade, the gear, and the glass. Utilization
of layered textures and projections was important for generating
reflection/bump maps from the diffuse texture, rather than making separate maps
for each type. If you can use the same texture map again with some utility
nodes/ramps to make the map you need, it can make things simpler and quicker in
the rendering process. Layered textures were also used for making transparency
maps for the labels and projections appear on the bottle and the box. With
different blending modes on layered textures with projections, a multitude of
different effects can be achieved.
As with the first
glass bottle, we had to set up the render settings and material attributes to
reflect (pun intended) what the glass should look like. We then went through
material attributes that mimic different fluids, such as translucency,
refraction glossiness, etc. My fluid was
an antique absinthe, which originally had a different label (I’ll explain
later). We added a separate spot light
onto the key light for caustic casting, and adjusted that to our liking.
After getting all materials, ramps, texture networks, and
render settings in order, we had a turn in with all separate render passes, to
troubleshoot any issues with our materials/textures that we should fix. Then it
was time to set up the render layers. We
made 3 separate layers, for the 3 different lights. Linking lights to render
layers and rendering them separately gives amazing control in compositing, so
nearly anything can be fixed after the render.
There was a cool area light, a warm spherical area light, and a key
overhead area light in the scene, along with the IBL. The caustic light was
attached to the key light and the IBL was attached to the cool light in the
render layers. I attached a depth pass
to the Key light render layer for a depth-of-field blur later in Nuke. With all the layer overrides and render
settings in place, I batch rendered a test to make sure everything was working,
and then batch rendered the final from the Maya Terminal so I could keep track
of the progress more accurately.
These 3 images are the result. Although they may look a
little strange from the start, when they combine in Nuke, it looks correct.
KEY LIGHT
WARM LIGHT
COOL LIGHT
Nuke Compositing~
With Nuke, anything is possible. I absolutely love this
program. As long as you can get good renders and isolate what you need, Nuke
can make everything better. We brought
our Key, Warm, and Cool render layers into Nuke and used shuffle nodes to
isolate the beauty, diffuse, reflection, refraction, indirect, and specular
passes with each of the layers. With all of these separate shuffles, you can
adjust or correct whatever aspect of the render you need, perhaps with the
assistance of roto nodes. I had to adjust the intensity of my caustics, so I
put a roto around that part of my key light layer as a mask on a grade node,
and then I could fix it from there. This
is my entire Nuke network- I’ll be explaining what everything means below:
The composite should look exactly like the beauty pass of
the render, so I shuffled out a separate beauty pass composite to make sure it
matched. When everything is combined to the final image, final compositing,
colourizing, depth blur, and any other overall adjustments can happen from
there. We were required to have a subtle vignette, created by an inverted
radial node attached to a grade node. We also needed some sort of colour
correction for this project~ we were encouraged to try out any methods to get a
variety of effects. The only other requirement was a depth-of-field blur, made
with the Zdefocus node in Nuke8 attached to the depth channel render pass from
Maya. I have 6 branches under the
initial composite; one for reference- with only the depth blur and vignette
applied, and 5 alternate artistic renditions of the image. I used a variety of
techniques-changing the light intensities of the 3 different sources, grade
nodes, colour channels connected to my vignette or other nodes- to create the
looks that I wanted. I also had different amounts of blur and different focal
points for each image. At the end of everything there are different grain nodes
added to each image for believability and artistic appeal. Here are my final
images. I didn’t use references for the style, I just wanted to feel it out and
see what I came up with.
For this version I wanted a clean-looking effect, from some kind
of studio light. The IBL intensity was lowered by a lot, and the warm light by
a little, making the Key light the primary light for this shot. I also
multiplied blue in the vignette channel to give the bluish feel around the edge
and colourized some other things.
This one uses the warm light as the primary light, lowering
the other two in intensity. I wanted this to look like a singular bright light
coming from the left, with possibly a distant window on the right. I needed to
lower the intensity of the bright specular, because it was too overblown for
the shot, so I used a roto and a grade node for that. I added an edge blur to
the red channel of the ref
I wanted to make a nighttime shot, or at least a dreary day
with not much light. The IBL/Cool light was intensified and colourized to get
the bluish effect. I took the warm light and increased the exposure on the red
channel more than the others, so it would mimick some kind of candle or dim
incandescent source.
This shot was intended to look retro- like an old photo from
the 1970’s feel. I gave the main light a yellow/orange hue, and colourized the
vignette again.
Ok, for this one I went a little crazy. I wanted it to look
alien, maybe radioactive or sick. I magenta-fied the image like mad, and added
a green vignette. I also hue-shifted part of the bottle fluid to make it look
like there was a green light behind the camera colouring the translucence of
the fluid. The vignette is coloured with green and so is the IBL/Cool light. I
also pushed the vignette really way further than it should be, which gives
kind-of an uncomfortable tunnel vision look. I was attempting strange, and I
think I pulled it off.
I had a lot of fun with creating different artistic styles
in Nuke, and if I had more time I would have done many more~ which brings me to
my last point.
Busted~
As you can see in my images, there’s a hard drive sticker
and a label that says “Busted Hard Drives” on it. That was not my original idea for this
shot. This is a result of a very
inconveniently- timed hard drive failure. I usually back up all my information
once in a while, so I don’t get left behind in case of a hard drive crash or
any other circumstance. I don’t drop my
computer, so I thought it was an unlikely occurrence for me. I’ve seen many other
students’ hard drives crash and I thought I was immune because it’s been 2.5
years and I have had no issues at all.
Well, I was wrong. I was nearly finished with this entire project and about an hour from turning it in, when everything froze and then I heard a mechanical clicking sound in my hard drive. My heart dropped immediately, because this 3-week project was just set back by two weeks because I had no back-ups. I back up my saves like an addiction, every single save is usually incremental-in case of corruption, but I sometimes neglect to back up my entire hard drive.
Instead of using my nice, complex, well doctored, custom
alpha-d textures for my labels, I now had to recreate everything and go with
simplified versions. My bottle was an actual antique Absinthe, and the fluid
attributes were still there because I had a copy of my Maya file. The label was
accurate to the real life label, with the tears and holes actually being cut
out by the Alpha in transparency- and it matched the bottle well. For the new
label, I picked another absinthe label that I liked and attached it to the same
bottle and fluid- if it seems mismatched to the colour of the fluid, this is
why. My new label was for a green, newer
absinthe, but I didn’t have time to go back and change my colour settings of
the fluid to match the label.
So, I took this opportunity to make light of my hard drive failing by putting it in my render- a hard drive replacing my Schrodinger’s cat (Animation reference. Check out the animated film-Schrodinger’s cat by Chavdar Yordanov. It’s awesome.) Typed letters read “Busted Hard Drives” rather than my custom-made marker “Schrodinger’s Cat” ones, but at least I could keep the blood close to what it was.
Closing- finally.
Okay, so I went through two weeks of work in one night, re-rendered and re-composited, and turned it in. I consider that a victory on it’s own, but I’m also still pretty happy with my final results under the circumstances. Not only did I learn everything once, but also I had to learn how to do everything much more quickly the second time around. I may be losing about 500gb of useful data from my hard drive, but since I’ve grown so much over the past two years, I’m really only losing some physical representations of what I already know.
This isn’t a singular case of my projects being lost,
although it is the singularly most inconvenient and largest. I’m going to see
it as a chance to start fresh in organization and growth toward being more
productive and smart about the way I work and it’s really a positive thing. I
had one incredibly bad day yesterday with the hard drive thing being only one
of the many thorns in my side. However, I start today fresh, and tomorrow with
a new hard drive, and I’ve gotten my work turned in and written my blog, so
this is a prime example of a learning experience for the better.
This VSD class has been quite fun, creative, and a great
learning experience. It’s given me a new
insight on lights and compositing, and accidentally~ on file management and perhaps,
life itself. One more month gone and the curtain call for CSF begins. I’m
excited for what I’m going to learn, and what I’m going to be creating in the
coming months with my cumulative knowledge of everything 3D.
Until next time, here’s a quote.
“What we observe as material bodies and forces are nothing
but shapes and variations in the structure of space.” -Erwin Schrodinger
Oh yeah. I’m also vegan now.
Not that that has anything to do with anything, but I am enjoying it.
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