Recreation using Maya and Renderman Rendered with Arnold
Render Time: 14min Render Time: 42min
Project PurposeThe main focus of this project was to work on our look development skills in RenderMan, try out Arnold, and to use that knowledge to
form a comparison between two different rendering systems. The project was quite a challenge because of the objects we created, most of
which are different types of food, and fruit which are infinitely complex to shade. This provided a real look at what these renderers could
do, especially under the time constraints.
RenderMan Settings Arnold Settings
Plastic WrapThe plastic wrap was quite an interesting problem to tackle. I started with a glass shader since it is the only option that allows clear materials
such as water, glass, plastic, etc. The topology of the wrapper was important to help give it interesting highlights, so make sure to have it
modeled as a crinckled bag as much as possible. This will then allow you to add a bump map to further distort the reflections, giving you
that plastic wrapper look desired. Turning the glass shader from thick to thin is also a very important step, to get rid of much of the refraction,
so it doesn't look like the cookie is in a solid block of glass. Next, the highlights were not quite as strong as I wanted, and you could not feel
the presense of the plastic as much as you should. To solve this issue, I went into my layer (where we will place the logo), and turned on the
specular reflections. This now adds a second layer of specular shine to the wrapper making it much more established. Lastly, to add the logo,
just add the image to the diffuse color of the layer, then a black and white version into the layer mask. The b&w version in the layer mask
will turn diffuse off in all places not covered by the logo which is important otherwise your plastic will be cloudy or totally opaque.
Fortune CookieThe fortune cookie was a bit more straight forward then the wrapper. I started with the basic shader, PxrDisney, grabbing the color from my reference
image. Then I added a darker shade of the same color to the Subsurface area, allowing some more variation of the color on my cookie. The next
important step was connecting a displacement map to give the cookie its texture. To do this, in the shading group tab, add an RMSDisplacement
node to the displacement material channel. This opens up this final window on the right here. Here is where you plug in the actual image or pattern
to use. For the cookie, I added a fractal pattern, which gets added to the "Scalar Displacement" tab. Before migrating over to change the fractal settings,
lower the displacement amount to about .1 to start to keep your object from being torn appart.
Cake & PaperThs tart cake was created in a similar fashion to the fortune cookie, giving it PxrDiseny, with the base color and a touch of subsurface, as well as some
displacement to give the desired deformations. The paper had a bit more to its creation. I modeled the paper the be more like the reference, but after a
few days of having the tart sitting on my table at home being moved around, the paper lost a lot of its creasing and started to soften out, so I decided
I would like to try to recreate the paper once it had lost some of its crease. For the shading, I added a LMDiffuse since I knew this would be the material
that allowed translucence. I gave the back color a hint of yellow, and raised the translucence a bit. This helped created a sort of fake subsurface, while
letting the object be more translucent. This was getting closer, but it still needed some more detail, so I added a layer to give us a very rough specular
highlight. Finally, I added a very light fractal displacement to make the paper look as it had been used and crumpled.
RasberryCreation of the rasberry was very interesting. I tried many different techniques to get it to the state I wanted, and found this gave me the most control.
I started with a LMDiffuse which allowed me to again, give the object some translucence, but this time, I added a bit of incandescense too! This helped
me make the rasberry feel almost as though it was filled with liquid. Professor Kesson also showed me the CutrVelvet node which he created. This node
allowed me to give the rasberry more dynamic shading even in just diffuse. I was able to excentuate the transluscence by giving the rasberry a slightly
brighter color around the edge. I also added a layer to the shader, which allowed me to give the rasberry a specular highlight. Lastly, I duplicated my
model, and scaled the copy up to be a little larger then the originial, then changed the shader to glass. This is how I was able to achieve the look of wet
sugar on the outside of the fruit.
FloorOriginally, I was just going to keep my floor the flat ramp backdrop, but my scene felt very empty and took away from the illusion of realism,
so I decided to try to mimic the texture on the table in the reference. To do this I created a PxrDisney shader, and gave it PxrVoronoise as displacement.
Then I raised the frequency and octaves significantly to get the desired grain.
Arnold Development:The way the shade things in Arnold is quite different than RenderMan. In Arnold, you start with the base material (aiStandard), and build it into the
desired substance. This required much more of a balance between each of the aspects since every attribute has a weight. Once I started to get the plastic
working, I encountered a handful of problems. Firstly, Arnold does not offer "thin" glass, which was very shocking to me since that is a feature many
other render softwares implement. Secondly, trying to make the object totally transparent, would change parts of other set attributes such as the logo
plugged into the diffuse color. My method to get around this, was to invert the mask that I used in RenderMan, to tell Arnold I wanted refraction, but
only in places other than my logo.
ConclusionOne of the things that came as the biggest problems to me in Arnold, was the method used for displacement. It felt extremely uncontrolable, and made
it very hard to change objects with the desired textures. One of the main problems I couldn't seem to find my way around was the need to subdivide
your mesh using attributes in the object shape node, under Arnold. It seemed as though to get the real map onto the object, you needed to turn this on,
which would then, changes your geometry in a way you may not have wanted. It seems as though they tried to make it less complex by putting everything
together, but didn't account for the challenge of having to make all materials starting with the same aiStandard.
Since the first time I ever used RenderMan was last quarter, I remember the learning curve trying to understand all of its intricate features. However,
I never felt as lost or frustrated with RenderMan as I have Arnold. Not only does it feel much less intuative, but it takes more than double the time to
to render an image of the same (or less) quality, which alone, for me, is a dealbreaker. Not only did the whole render take longer, but it also could
take up to a full minute in many cases before it even started rendering. After seeing the price doesn't differ much between these products, I would choose
RenderMan hands down.