2D, 3D… 2.5D?? July 8, 2009
Posted by Mok Oh in panorama.Tags: 2.5D, 2D, 3D, Earthmine, ETech, EveryScape, extrinsics, Google, intrinics, Mapjack, web
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EveryScape's "2.5D" Local Business Webscape Demo
When I say “2D,” people understand. When I say “3D,” folks get that too. But when I say “2.5D,” I either get a “huh?” or a “hm..” Yes, dimensions are typically in integers, so it’s a fuzzy description for sure. When I say 2.5D, I mean visual representations that look almost 3D but not quite. More specifically, in my context, I mean connected series of immersive panoramas.
Ok, some nerdy stuff (but don’t fall asleep). Typically, 3D in our context means three orthogonal axes in space, let’s call them X, Y, and Z — hence, the 3 dimensions. When a first-person or a camera or a viewer is involved, we need to add a couple more dimensions Phi and Theta for looking up-down and side-to-side. So position (x, y, and z) and some viewing direction (phi, theta) consist of 5 dimensions (also called the extrinsics). Yes, there’s something called the intrinsics as well, but that’s for some other discussion — it just means what type of camera and lens you’re using.
So, what’s my point? My point is 2.5D really is just a figure of speech. But more interestingly, I think that 2.5D way of representing our world in a digital fashion is really useful.
I gave a talk at an O’Reilly Emerging Technologies Conference early this year titled “2D, 3D… 2.5D?” The abstract was as follows:
“Historically, 3D on the Web has always been associated with difficulties. Although 3D has been around for decades, from research labs to gaming to visualization of a 3D earth, there are numerous reasons why 3D is still having majority adoption challenges. On the other hand, digital photography (and video) have blossomed well into the world-wide consumer market, from both hardware (e.g., cell phones with cameras) and software perspectives (e.g., Flickr, YouTube).
In this talk we delve deeper into the benefits of a “2.5D” representation of our world, leveraging both 2D photography and 3D graphics and vision techniques. We open up a discussion for why such difficulties in 3D realm exist, what/how we can benefit from digital point-and-shoot photography, and further discuss the benefits of creating a “2.5D” representation—more specifically from the mirror world and web perspective (e.g., Amazon A9, Google Street View, EveryScape).
We will discuss the pros/cons of 3D using specific examples (e.g. Google Earth, MS Virtual Earth, Sketchup, Maya, etc.), 2D (e.g. digital photography, photoshop, jpeg, flickr, etc.), and 2.5D (e.g. EveryScape, Google Street View, MS Photosynth). Below is a table where we compare the each of the 3D, 2.5D, and 2D with some parameters, in which we argue all must be in the “easy” category for mass adoption success. Mass adoption of 3D may be years (or even decades) away, and various 2.5D solutions are filling in some of the needs now. We further discuss EveryScape’s specific journey in research and development—how and why we ended up where we are today.”
The point is that while scalable 3D isn’t quite here yet for the web and mass adoption, 2.5D technologies are filling in the gap (e.g. EveryScape, Google Street View, Earthmine, Mapjack). They are emerging indeed!
If there’s enough interest, I will put up my slides. Pls let me know.
Found an interesting game-related article on 2D here: http://midlifegamer.net/2009/06/24/2d-or-not-2d-that-is-the-question/
2.5d is the immediate and obvious next step to 2d maps at any scale. But, it’s already been done, if only now being implemented at a large scale by Google, Navteq, Nokia’s Ovi. And, more critically, a lot of people at geospatial conferences refer to that as 3d, and build standards and information models around it when not understanding that true 3d is our yet unachieved goal. In other words, you are right in referring to hollow 3d extrusions and representations as 2.5d but a lot of other refer to it as 3d, and it isn’t.
What I was trying to say in the Twitter comment is that 2.5d is great for display of static bodies and the results of structural and thermal analysis (take a mesh, throw a fabulous, true-to-life texture on it, throw it in game engine). But, in order to allow for real AND location-aware representations of the earth, cities and structures, especially when it comes to architecture, engineering, construction, defense, etc. and the interaction of humans and nature with this infrastructure, the geoweb has to start talking the information modeling, storage, retrieval and simulations of such solid 3d.
Yes, agreed. 3D is necessary many applications.
We are actually in process of getting some non-static scenes in 2.5D. Stay tuned!
Also, I see you went to Oberlin. You’re not from Ohio, by any chance?
I’m not from there, but from pretty much everywhere else. You?
Also from everywhere else, but I live in Ohio now, an hour or so south of Cleveland.
Interested in seeing the slides, Mok–and would love to syndicate this on blog.everyscape.com.
Thanks, Rebecca. Absolutely!
[...] mentioned some of them in my talk at ETech 2009 and Where 2.0 2008. The list may vary depending on specific applications, but for [...]
Hello Mok,
I’m Interested in seeing the slides, also want to ask where I can find the table where you compared between the 3D, 2.5D, and 2D with some parameters.
Many thanks in advance
hey there i don’t know if this post is still active but i’m doing a short literature review for my project proposal (which is on 2.5d)
have you got those slides you talked about still available?
im basing my paper on if 2.5d is liberating the dimensions?
regards
Hi Mok,
Please share those slides.
Hi Missy,
Sorry it’s been a while since my last blogs. I will look for the slides and put them up somewhere.
tx!