As planned from last time, we carried on with our look development session with a focus on developing materials for a potted plant. Firstly, a quick recap on what look dev is:
“It is the process of designing, defining and agreeing on the final look of 3D CG content in productions.”
Like last time, I would like to reiterate that it exists in 2D as well, but for our lesson, we were looking at analysing materials and design images along with using textures to build an approved look. This meant that we needed to utilise knowledge on topology, texturing, shader design, lighting and some compositing as well. It also meant that we needed to set up a look dev scene in Maya, which I hadn’t heard of before. It is a pre-built scene with a turntable, VFX kit, lighting or chrome probes and a Macbeth colour chart. It is an industry-standard setup for creating lighting and consistent shaders and is practically ideal for presenting 3D models in a professional manner.
The chrome probes allow you to see your HDRI and how the current lighting affects a mid grey base colour, whereas the Macbeth colour chart lets you calibrate your colours. The slate image is often used for notes and reflects what you could see on a set in real life. From the image that I could see, I was quite impressed with the modern, polished arrangement and I was quite excited to see the example shown to us of what could be achieved using such tools. The video that I watched as one of a beetle model, and it was extremely well done, but here I have found an example that shows how the look dev set-up can be utilised. As you can see, the HDRI is rotated as well, to show how the lighting works on the armour and can be seen in the chrome probe at the top left.
Maya: Render & Lighting Setup – Demo
We opened plant scenes in Maya and started to clean & prep. The first thing that I did was combine all of the components of my plants in ‘mesh’ to make sure that everything was stuck together as it should be and there were no loose parts that could be left behind when moving the model around. I had two plants and debated doing both but settled on just the one since it would be more aesthetic on the turntable. Speaking of which, we had to import in next and the steps were a bit more complicated than usual, meaning I had to listen carefully and take notes, otherwise I would be a bit lost.
- Enable the grid and scale the plant up to match it, since the look dev set-up works on a different scale
- In Insight, go to the look_dev file and right-click
- Select 7-Zip and then click ‘extract to look_dev_ref…etc.’ (the file name)
- In Maya, import from Insight’s unzipped folder – look for the ‘ma’ or ‘mb’ file.
This is what I saw once the set-up appeared and despite enlargening the plant pot earlier, it was still tiny so I had to scale it up further. Other than that, everything looked as expected. We had to find a little icon under ‘Bonus Tools’ which linked to the render settings and click that to open up the window. In ‘system’ we then changed the render device to GPU, since apparently, it is far better to use than CPU. I’m still not quite convinced on that but carrying on, we also went to the ‘common’ tab and in ‘presets’ we changed the image size to HD_1080. We had done everything we needed in the render settings and closed the window to move on to adding a skydome light. It was time to choose an HDRI!
Jake introduced us to this amazing website which I am quite shocked that we haven’t used before and is in fact free. It is called PolyHaven.com and has HDRIs, textures and models available for free download and use. The library has some professional-looking stuff – I definitely won’t be returning to Google for my backgrounds in the future. After some browsing, I chose one that I liked and applied it to my scene. When opening up the Arnold renderer, it took longer than usual and all I could see was a black screen for a couple of minutes. Soon after though, my plan appeared in a beautiful garden, more HD than I had ever seen before in my renders. I don’t know if that’s the GPU at work or PolyHaven!
I wanted to get rid of the screen at the back, so I hid it along with the frame by selecting and pressing ‘H’. We then had to turn back to the board to learn more about the following steps which included adding colour and texture to the actual plant.
Shaders
Shaders define how an object will look by computing each pixel in an image during rendering. They are all built from similar components although the designs and requirements can vary between different rendering engines. They are most commonly used to produce lit and shadowed areas in 3D models but now perform a variety of specialized functions in various fields within the category of computer graphics such as video post-processing unrelated to shading. One such method is PBR, which stands for Physically Based Rendering. This workflow uses a texture map for each shader component and is used by most VFX companies and games studios because it saves time. Artists are not required to dial in specific values for each component during rendering and the popularity of the method has certainly been taken advantage of, with companies selling texture sets for PBR workflows and software such as Substance, Marmoset and Quixel.
So what are the components of a shader? It was good that these were explained to us since we would be using the settings in the panel quite a bit.
- Base / Diffuse – Colour
- Specular / Metallic – Reflection of light
- Roughness – Smoothness or sharpness of a surface
- Transmission – Light diffusion
- Subsurface – Light scattering
- Translucency – Alpha of your model
- Emission / Incandescence – Emitting Light
- Normal, Bump, Displacement – 3D detail
One of those, in particular, had a slide dedicated to it for our understanding and because the focus of the lesson is on plants. It is subsurface scattering which is a phenomenon of light where it scatters in semi-translucent materials. This mechanism of light transport can be seen in organic matter and skin. Things like plants and fruit will exhibit some amount of it and we even tried it ourselves by putting our fingers over the torchlight of our phones. With everyone, the light scattered a little differently; some people reported that they could see their bones, but for me, my thumb just glowed red.
This is also partly what gives leaves their strange glowing quality when basked in light. We were shown an image and asked to describe it in a similar manner to how look-dev artists have to evaluate and understand the appearance of objects. Not just the how, but also the why – the science and logic behind their textures, colours and other features.
My description: Burnt, crisp edges, semi-translucent, spiky, veiny
Slide examples: Shiny, glossy surface, has a wide range of greens that vary throughout the leaf structure, light can pass through it with a light green, yellow colour, leaf veins and dimples can be seen and felt in the surface
Maya: UV & Shader Setup – Demo
Now that we had a good grasp of shaders and how they link to the appearance of leaves, we could apply some to our plant models! Back in Maya, we selected our plants and went to ‘UV’ at the top, where we clicked the option ‘automatic’, without selecting the tickbox. in the industry, you would usually have to cut up maps but for now, we went with Maya’s auto mode. After this, in face mode, we had to separate out models (a little annoying after having combined them) into separate areas based on the materials required. For example, I had to split mine up into pot, soil, main plant and plant spikes, since Bear’s Paw has little red claw-shaped spikelets at the top that are usually a different colour from the rest of the plant.
Once the mesh was separated and ready, I could finally add the materials to each. I chose ‘aistandardsurface’ and started tinkering with the settings to the right. Thanks to the gained knowledge of shader components, I actually had more of an idea of where to go and what to change with my result in mind, unlike my usual blind experimentation. My first aim was the green parts of the Bear’s Paw – the paws.
They have a very unique, cute fuzzy texture, and I didn’t know how I was going to achieve that so I focused on the colour instead. At first, they were far too shiny and plastic-looking, but after I turned down the specular weight and increased the bump surface, the texture improved slightly. It was here that I realised that my spikes had reverted back to their original form – the poly cone. Because I had separated everything, I had removed SMP and had to go back and reapply it to all of them. This didn’t take too long but I was aware of how long we had for this task (not very long) and how much I had yet to do. Without fully finishing the green parts, I had to throw on some colour onto the pinkish-red ones.
You can also see something applied to the soil in the image above. This is because I wanted to make the soil very realistic and apply a texture from PolyHaven instead of just making it ‘brown’. Their library looks so cool and I enjoyed scrolling through and seeing what kind of natural textures they had. The difficult part came after I downloaded my chosen one and had to apply it. My first attempt went wrong because I clicked the wrong file in the unzipped folder, hence why it was all black in the render. I then went back and chose the PNG, and also opened up the UV editor to enlarge the plant pot, so that the detail of the soil could be seen.
I really wish that PolyHaven had a texture similar to that of Bear’s Paw because as good as my soil looked, the plant still wasn’t as realistic as I would have liked. I think that I needed to spend more time in the material settings but we had run out and had to export our plants. I quickly added a metallic shader to the pot, clicking the wrong file by accident again and making it black but not having enough time to go back and change it. I shift selected the entire model and went to ‘file’, ‘export selection’, changing the file type to ‘OBJ’. This is as far as I got:
I think that it looks very nice! Considering all of my previous renders, this is definitely the most professional looking one that I have done. I would have liked to make the plant look more alive but some of the fuzzy texture does come through thanks to my playing around with ‘bump surface’. Overall, I’m happy to have learned more about shaders and what each of the components actually does, since this helps a lot with getting nicer renders – and the final result is what most people see. The final outcome of the lesson is one that I still need to work on – adjusting the parameters in such a way as to get the desired look, which I suppose is where to look development artists excel. Getting a taster of what they do has been really interesting, especially since I have always loved that final stage of the modelling process, where you get to see the subject come alive with colour and texture.