There were fewer tables with rows upon rows of glass pipes, apparently replaced by booths with high-end technology that takes a pound of dried marijuana and extracts oil concentrate in 20 minutes.

Fewer t-shirts, more blazers.

On a rainy Saturday, hundreds of people packed the Hynes Convention Center for the third annual New England Cannabis Convention, months after Massachusetts voters broadly legalized marijuana for recreational use.

Attendees were not allowed to smoke or vape inside the center: Signs were posted outside the entrances and inside vestibules as reminders. The convention's main focus wasn't on smoking anyway, and centered instead on growing, cultivating and protecting the substance that remains illegal at the federal level.

One vendor touted a $1,995 machine that promised to vacuum-seal your stash, at a rate of 360 packages per hour. Another, Arch Solar of Portland, Maine, showed off a tiny model of the "Grow-Box," an hybrid indoor-outdoor greenhouse that seeks to take advantage of natural light in a bid to offer savings on energy costs. CannaCloud, based in Stoneham, Mass., seeks to become the "Keurig" of the marijuana world through a vaporizing system based on little pods.

But the industry still has a ways to go. The marijuana plants many vendors used to help model their indoor growing lights were plastic. The vacuum sealing machine's demo had broccoli inside instead of cannabis.

And inside the convention hall, people by and large declined to stop and chat with reporters. One man, who said he is an engineer, asked that his name not be used as he relayed how he's scouting out the technology on display for his wife. She's looking to start a grow facility in Massachusetts, he said.

Looking around the floor of the Hynes Center, he remarked that the scene appeared closer to an electronics convention or a medical conference than a gathering of marijuana enthusiasts.

Marijuana is legal in eight states, including the entire West Coast, Massachusetts, Nevada, Colorado, Alaska, and Maine. Legalization activists are hoping pass bills in six states, including Connecticut, Delaware, Maryland, New Jersey, Rhode Island and Vermont in 2017 and 2018.

Medical marijuana is legal in more than half the country, including Massachusetts.

Nic Easley, CEO of Comprehensive Cannabis Consulting, offered attendees at the convention a rosy future for marijuana. "There will be fields in Iowa" full of marijuana where there was grain, he said.

"Start thinking about it as an agricultural commodity," he said.

Steve Flaks, vice president of sales at BioTrackTHC, a seed-to-sale software company, said he expects a "whole new wave" of people to get into the industry over the next few years, leading to a "professionalization" of the business.

"There's a big shift coming," he said during a panel on the marijuana industry.

That shift will extend to politics, activists say.

Kamani Jefferson, president of the nonprofit Massachusetts Recreational Consumer Council, said he previously didn't care about politics.

But now he's interested in keeping tabs on Massachusetts lawmakers who may change the law voters endorsed in November and the 2018 race for governor, since the executive branch will play a role in implementation of the law.

Gov. Charlie Baker opposed the ballot question that legalized marijuana, as did most elected officials across Massachusetts. They warning that it would bring a massive industry harmful to children, and as many pot shops as there are Starbucks and Dunkin' Donuts stores.

"This industry's all politics," Jefferson said. "I care because I care about marijuana."