3D space - perspective v's rotate Y

arfa · Post by **arfa** » Mon Feb 09, 2009 6:44 am

There are several procedural questions around 3D space but first...

I wonder at the relative merits/pitfalls of drawn perspective v's rotate Y.

One situation I have been working on:
View is (interior) to a windowed wall. Person sits at a table reading. Knock knock.
Pull back, track left and pan (not quite 90) right to adjacent wall with door. Door opens, etc.
I have tried drawing using perspective and also setting the wall with the door at 90 degrees to the window wall.

Allowing that much else with the s'ware is new I have mixed results with both approaches.
I could of course just cut from one view to another but...

Thoughts, suggestion, links etc. please.

- arfa

Mikdog · Post by **Mikdog** » Mon Feb 09, 2009 9:57 am

Sounds overly complicated. Rather just cut to the different view, animate the door opening without fiddly camera movements. If you're intent on using the 3D (2.5D) camera, I recommend pulling the camera out quite a bit first - not zooming out but moving it a greater distance away from your subject, so that slight movements towards the camera don't look gargantuan. But if you've planned your scenes out I think generally I get a much better result by doing scene by scene rather than trying to work with fiddly 3D moves and camera movements...aah.

slowtiger · Post by **slowtiger** » Mon Feb 09, 2009 10:44 am

Did you do some research about cylindrical perspective as it is used in classical animation in simulating a camera turning around inside a room? For me, this would be the easiest way to accomplish the task.

Mikdog · Post by **Mikdog** » Mon Feb 09, 2009 5:13 pm

I must admit I've never tried cylindrical animation, I think I know where you're getting at though. I've seen some awesome panning shots of city streets, remember seeing some great Pinnochio backgrounds that had these weird perspectives but when looked at one field at a time the effect must've been cool.

Sorry, my fault for not taking time to read the question properly.

So instead of trying to simulate a 3D environment in AS, why not create a flat background scene that LOOKS like its the other wall when you pan along it in a 2D space?

Slow's always got great tips, great resource to the forum with real-world experience.

I'd be interested to see your outcome, what method you use arfa.

chucky · Post by **chucky** » Mon Feb 09, 2009 8:14 pm

If you make a 3D ROOM, and this is in line with Mikdog's point about lens size, make sure the room is large enough to have enough tolerance for your lens size. This will allow you to use longer lenses without being stuck ,looking at a just small patch of wallpaper or having extreme distortion from icky wide angle lenses.

arfa · Post by **arfa** » Tue Feb 10, 2009 9:28 am

I suspect, both from your comments and my own wrangling with perspective in 3D, that I will focus more on the drawn approach.

I am not that experienced as an animator so 'cylindrical perspective' is an unknown. I guess, thinking on, i have seen Victorian 'what the butler saw' type apparatuses (apparatii?) with cylinders. I will do a search and see what comes up.

Lens length is something I am familiar with and has already presented itself as an issue during my experiments.

I wonder generally about the use of AS 3D space. Camera movements are clearly useful but I wonder how many of you zoom about in 3D as per the AS Animation>3D Scenes tutorial (with the trees - folding the ground on X rotation). This may be a bit extreme but I would appreciate any comments on this.

realsnake · Post by **realsnake** » Tue Feb 10, 2009 10:14 am

Heres an example

http://www.mediafire.com/download.php?ozwnwnmttzy

arfa · Post by **arfa** » Tue Feb 10, 2009 10:47 am

Thanks for the example.

Just to be clear around terminology:
Would you call this 'cylindrical perspective' or 3D space? or am I getting mixed up? :}

I have tried searching the web for "cylindrical perspective" but there is little available. I am on dial-up so it is slow.

I have made a quick study (running out of play time) and my first thought is "would this work as a room? With a floor and/or ceiling?" I will have a go.

thanks again - arfa

slowtiger · Post by **slowtiger** » Tue Feb 10, 2009 12:19 pm

Here are some examples to give you an idea:
http://farm2.static.flickr.com/1382/545 ... 8c.jpg?v=0

The trick is to only show such a small portion of the BG that nobody notices the curved lines.

Normal perspective:
http://2.bp.blogspot.com/_QdHn8FT7SdY/S ... nt08sm.jpg

arfa · Post by **arfa** » Wed Feb 11, 2009 7:45 am

Thanks slowtiger - I pretty much thought that's what cylindrical perspective is.

On the terminology front I would call the example that realsnake offered 3D space - with layer Y rotation.

I eventually found a few web pages on cylindrical perspective but, as per your example slowtiger, they were all photo examples.

So, the next question - a bit outside the core AS realm - but - "how to draw such a thing?" Any suggestions? I have copied your flickr example which I will try outlining and play around with.

slowtiger · Post by **slowtiger** » Wed Feb 11, 2009 8:10 am

You could take one of the photos and draw on top of it?

You need to have some experience in drawing in perspective. But you also need some knowledge about how to construct a pan in animation. Don't worry too much about any "correctness". The trick with such a pan background with round perspective is to add enough free space (= colour without too much detail, like a wall) and to use it quite fast.

I made a quick sketch about your specific problem.

First row shows your two shots, drawn individually, in perspective. Second row shows the two perspectives combined. The red frame indicates what's visible for the camera. The smaller that frame is, the less likely the audience will spot the trick. The area B is the one which usually gets stretched a lot, because that's the part the camera pans very fast across.

synthsin75 · Post by **synthsin75** » Wed Feb 11, 2009 4:05 pm

Huh, I was going to point out 'Underground' here:http://www.lostmarble.com/ But for some reason I can't view it anymore. Same for the Lostmarble gallery. Anyone else able to view them or have they been taken down?

Anyway, it showed a good example of using cylindrical perspective while going from a landscape to down a shaft.

arfa · Post by **arfa** » Thu Feb 12, 2009 10:22 am

Thanks for the sketches slowtiger. Interesting to see that you work R>L.
Yes, I tried outlining the shot of the living room. There was a bit more distortion than I would prefer.

I like the possibility of being able to slow pan but will certainly experiment with the 'blurred middle' approach.

Considering my initial question - drawn perspective v's 3D - The drift here clearly seems toward the drawn method. Here is my current approach. Not exactly rocket science but quite simple. Center the corner. Set up the shot on the window to start then track/pan to the door.

Underground (3.25Mb) is at:
http://www.lostmarble.com/moho/gallery/ ... deos.shtml
I will study that a bit later. Thanks for the lead.

Off to the woods - arfa[/img]

synthsin75 · Post by **synthsin75** » Thu Feb 12, 2009 3:52 pm

Don't upgrade to Flash player 10 before watching it, that was my problem.

arfa · Post by **arfa** » Fri Feb 13, 2009 7:50 am

I am outputting to FLV and use Wimpy (free) as my standard player. SWF files I can run in the browser so don't use Flash Player but thanks for the tip.

and on - arfa