tom cruise edge of tomorrowCourtesy of Warner Bros. Pictures"Edge of Tomorrow" does it right.

Is 3D movie technology a money-making gimmick or a true innovation? The answer is a little of both. Some movies use the technology to create more wonderfully immersive scenes, but others do little with the technology or even make a movie worse.

Given the hit-or-miss nature of 3D and the steep cost of a ticket (adding $4 to an already expensive $14.50 New York City movie), I've learned to look up 3D evaluations like the ones put out by Cinema Blend. Just recently, Cinema Blend's Kristy Puchko warned me in time that the 3D version of the otherwise excellent "X-Men: Days of Future Past" is a dizzying waste of money.

For further insight into when 3D is effective and where the technology is going, I emailed Sean O'Connell, Movie Content Director for Cinema Blend. My questions and his responses are below:

What are some of the best examples of 3D in movies and what makes them so good?

Recently, Doug Liman's "Edge of Tomorrow" boasted the best 3D. Camera positioning in the action sequences and a real focus on "before the window" imagery (meaning stuff that comes off of the screen and into the theater) helped put the audience into the movie. And that, to me, is the point of 3D. It should be used as a tool of immersion, a visual device that helps you feel like you are part of the story. When we watched Alfonso Cuaron's "Gravity" (another amazing example), we felt like we were in outer space. That's why James Cameron's "Avatar" still stands as the finest example of what 3D can do. Audiences felt like they visited Pandora with each screening, because his use of 3D placed us INSIDE the movie. 

Outside of that, 3D tends to work best in the field of animation, which is why the 3D in "How to Train Your Dragon 2" and "The LEGO Movie" amazed.

lego movie characters YouTube / Lego Movie"The LEGO Movie" does it right.

What are some of the worst examples of 3D in movies and what makes them so bad?

3D, as a tool, is improving, so you have to go back a few years to pull examples of truly offensive 3D. After "Avatar," studios raced to make everything 3D, just so they could charge extra for a ticket price. Post-converted 3D damaged movies like "Wrath of the Titans," Disney's "Alice in Wonderland," and a slew of horror movies that wanted to capitalize on the gimmick without putting in the extra effort. 

The 3D in these films are bad for two main reasons. If and when you are going to use 3D, you have to plan your shots differently. Applying 3D to already-filmed material rarely helps. You are forcing a square peg into a round hole, essentially. Movies like "Life of Pi" and "Hugo" are plotted and conceived to take advantage of the tricks 3D can offer a storyteller. Movies like "Texas Chainsaw 3D" are not. 

The other detriment to 3D in these instances is the absence of light in a 3D movie. 3D really needs brightness and saturation. Horror movies and period adventures (like an "Underworld" movie, or "I Frankenstein") immediately are behind the curve because their visual palettes are dark, which reduces the effectiveness of 3D behind the slightly shaded glasses. Daytime scenes in "Thor: The Dark World" or "Captain America: The Winter Soldier" help 3D action sequences pop. Nighttime fights in horror films often do not pop, and that's a problem.

texas chainsaw 3dLionsgate"Texas Chainsaw 3D" does it wrong.

What does it mean to shoot a movie in 3D as opposed to shooting in 2D and converting it? How big a difference does this make?

Some directors film using 3D, stereoscopic cameras, which create the two versions of the image needed to create the immersive effect on one's eye. James Cameron. Alfonso Cuaron. Martin Scorsese. They commit to 3D cameras (which are still a developing tool). It is the most natural way to capture imagery to be presented in 3D. But it's harder, because the industry is still experimenting with the tools, and costs are high. 

It is easier, but less effective, to shoot a film with traditional, 2D cameras, and "add" the 3D later, in post-production. But the mere act of "conversion" opens the door to possible problems. Higher frame rates on certain movies (the recent "Hobbit" films, for example) can create visual hiccups. Anytime images are converted in post-production, the slightest tinge can create lag, which tricks the eye. Manipulating ANY image leads to possible problems, so movies filmed in 2D and converted to 3D have to have near-perfection to be great ... and near-perfection rarely happens!  

How has 3D technology improved in the past few years and what do you expect going forward?

The more you do ANYTHING, the better you will get at it. The more time that storytellers have had to think about 3D, the better (and more innovative) their approach to the tool has become. We are seeing more movies — like "Hugo" and "Gravity" — that basically exist to take advantage of 3D. It is a big part of the storytelling process. That has been the biggest improvement. Movies that incorporate 3D from the beginning stages of the movie — not shoehorned onto the movie late in the game.

But wearing the glasses is still a pain. And so, going forward, I think we're going to get to a point where 3D will be possible without glasses. Spielberg is leading this charge, as well. The development of projectors that will present a 3D image without the need for glasses. It sounds like voodoo! But it's coming, and soon.

What are the biggest pitfalls of 3D in movies?

To me, the biggest pitfall when it comes to 3D is the cost of a ticket. Because 3D is basically applied to every animated movie, whether they need 3D or not, it  is becoming so much more expensive for a family to go see the latest Disney, Pixar, or DreamWorks movie. Of course, families CAN choose 2D versions of the same movies. But "How to Train Your Dragon 2" loses some of its appeal if not seen in 3D ... and that's a costly night at the movies for a family of four.

Where do you see the biggest potential for 3D in movies?

In the right hands, 3D can create imaginative worlds that audiences want to revisit time and time again. Truthfully, I prefer IMAX as a visual tool. But when used properly, by creative storytellers, 3D can immerse us in unexpected worlds, and there's potential for eye-popping, memorable sequences for years to come.