While many live-action features include an increasing amount of CG animation, the movement has gone both ways, and animated features now also boast effects that are increasingly sophisticated and often highly realistic. It is a trend validated by the Visual Effects Society, which honors effects in animated films at its annual VES Awards.

One film that exemplifies the trend is the Oscar-nominated “Coco.” With huge crowds and complex environments, the Pixar toon exemplifies the huge role vfx now play in feature animation.

“We have lots of people who come from visual effects and programming,” says Pixar’s Stephen Matthew Gustafson, whose credits include both “Coco” and “Finding Dory.”

Both films have earned Gustafson VES nominations for visual effects, and he’s seen the scale of challenges grow. “We’ve made lots of improvements across Pixar’s entire pipeline that allowed us to scale up,” he says. “ ‘Coco’ took on the brunt of getting that technology in place.”

Crowd simulation techniques continue to improve. However, notes Gustafson, “sometimes when the crowds get really heavy we have to find clever ways of making it look like there’s lots of variety, while really using lots of duplication. There’s still a lot of hand work required. You can use simulation to get 90% of the way, but then the director asks for the other 10%. That’s where the work is.”

Creating “directable simulation” has been a longstanding challenge. Water simulation software enabled PDI/DreamWorks to animate a climactic flood in 1998’s “Antz,” and earned Scientific Achievement honors from the Motion Picture Academy. Ken Bielenberg, who supervised the visual effects for both “Antz” and this year’s Oscar-nominated feature “The Boss Baby,” has witnessed the evolution first-hand.

“In the early days we would say, ‘We can do one or two big scenes. If you want the flood in “Antz,” other sequences need to be fairly simple.’ We still negotiate because budgets aren’t endless, but the amount of pushback is so much less.”

Bielenberg, BAFTA-nominated for work on Oscar-winning “Shrek,” has seen increasing latitude when dealing with environmental simulations like forests. “I headed DreamWorks’ effort to create a tree library, because that’s something you hate to spend money on.” But “The Boss Baby” director Tom McGrath (known for DreamWorks’ “Madagascar” franchise) wanted more stylized environments. “Trees from ‘Shrek’ would have been too realistic,” Bielenberg notes. “Commercially available software is better suited to creating realistic-looking trees for live-action visual effects, but [it] hasn’t worked for us.”

A balance has to be struck between realistic environmental effects and the stylized characters that populate most animated features. Bielenberg, who had to integrate fully 3D-CG characters into 2D fantasy effects for “The Boss Baby,” says: “There’s always a check-and-balance with directors. Visual-effects people tend to want to do MORE, because it’s fun.”

Pixar visual-effects supervisor Greg Gladstone echoes that sentiment. “As the effects group on a movie, we advocate for a level of added detail,” he says. “Having things look more realistic and more detailed comes out of our ability to do a little bit more with newer technology.”

Gladstone’s vfx team earned a VES nomination for “Cars 3,” which simulated the dirt and dust surrounding the film’s four-wheeled stars. “‘Cars 3’ was an action movie that called for tons of effects,” he says. “We had cars going crazy on mud tracks, and skidding on concrete with smoke coming from their tires. I spent a couple of months just optimizing how to generate smoke and dust so that one artist could do 10 shots very fast. Production times are actually decreasing, so we need to do more in the same amount of time.”

Having previously worked on the “Madagascar” franchise and “Happy Feet,” Gladstone observes: “The difference now is that we’re creating environments down to the needles on the trees. But if it’s a good story, you stop paying attention to environment and start enjoying the imagery.”