Cati Grasso: “Details are Key in 3D”

Former Gnomon & Universidad de Palermo graduate Cati Grasso has a lot of talent. She did impressive work for Pixar, worked with various advertising agencies. In our exclusive interview, organised with the help of The Rookies initiative, Cati was kind enough to talk about her approach to environment design, work with details and careful optimisation. Great advice for 3d artists inside.

Introduction

My name is Cati Grasso and I’m an environment artist, specialized in modeling organic and hard surface sets and props. Graduated in Audiovisual Design at Universidad de Palermo, Argentina, and attended courses abroad, like Maya fast track at Gnomon School of Visual Effects. Worked as a technical intern at Pixar (PUP 2013) and as a 3D modeler/generalist in advertising agencies back in my home country. I was part of the fixing and rendering team in the movie: Underdogs. I’m currently at SCAD working towards my master’s degree in Visual Effects.

Production Process

When producing this kind of work I usually start by finding a great concept and inspiration. I always try to look for concepts that tell a story and create everything in the scene so that it contributes to the storyline. Once this is done, I find it very useful to draw or photoshop exactly what I want to achieve in 3D. I then place some proxy objects in the scene and create the camera and layout. After showing this to my peers and professors, and going over their suggestions, I take some time to analyze the need for detail of each object. In this case it was very clear that the view of the spectator will be focusing on the bug and it’s mechanism, so I gave full priority to that. The following stages of production in this case were modeling, Uvs and rigging. After that, I simultaneously worked on lighting and shading. The last stage was to add details like the fur, which I left for the end to add only if I had enough time. To finalize, I created the needed render passes and layers to be able to composit some of the parts individually, like for example the wings. After rendering the whole sequence I composited it using Nuke and outputted my final movie.

Useful Software

To model the assets I used Maya. What I liked about this work is that it allowed me to combine organic, hard surface modeling and trying some different techniques, like for example using nCloth to achieve the shape of the transparent part of the wings. For the mechanism I used a lot of instancing for the small parts, like the screws. To give the impression that they were different I used a simple python tool I created to randomly rotate, scale and translate all the selected objects. For the body of the bug I modeled all the parts in the right side using polygons, and once I was happy with the result I mirrored them to form the whole bug. I then made some alterations in each part individually to create a more organic feel.

Painting Materials

To create my textures I usually use a photo for the base and then paint on top of that to achieve the final result. I painted the basic textures using ZBrush for organic objects and Photoshop for hard surface models. To generate some irregularities I created a bump map to use in the shader of the bug’s body. It’s really important to generate great texture maps, but it’s also important not to forget to work on the qualities of the shader. For this, I created some spheres to which I applied some of the shaders in the scene and made tests on how the materials reacted to lighting and movement. It was also important to add some bump and irregularities to the metallic shaders, so that they didn’t look like they just came out of the factory.

Details

Details are key to the final quality of every project. I usually try to create the base of my scenes really fast and then spend most of the time adding details and variation. When having a lot of similar items, like the gears in this case, a small amount of variation between them helps improve the realism. In my opinion deatils are the key to generating great images. Every detail should be added having into account the protagonism of the asset and contribution to the story.

Challenges

For me one of the main challenges I always have when creating scenes with a lot of assets is optimization. There are a lot of ways to optimize the scenes and assets. I find it very useful to work with different levels of detail, not only for geometry but also for the textures. To approach the production of 3D models, it is very important to plan ahead and evaluate the need for detail in each particular case before starting to create any models.

Another very important aspect of production, which is also related to optimization, is time management. Like in every production, when creating work of my own, I like to plan ahead and organize the stages of production and priorities to make the most out of my time.

Hope this was useful. You can also visit my process blog for extra details.

 Cati Grasso, Environment Artist

INTERESTING LINKS

BUILDING CATHEDRALS WITH 3DS MAX

ACHIEVING A PERFECT LOOK OF A 3D SCENE

3D MODELING FOR GAMES & FOR SHOW