View Full Version : Z-distanges between 2d layers (AE)

 halen01 January 2010, 02:10 PMGreetings. I'm new to this part of the forum, and this might be a noob question. I would like to make some small camera movement to the mattepainting, but how do you decide z-distanges between layers to make movement believable? (best way would probably to project on 3d geometry, but looking the quick, dirty and possibly easier way first...) Is there some maths of tool or thumb rule how it should be done (using after effects)? Image here about what do I mean: http://www.halen.org/releases/matte/camera.jpg (http://www.halen.org/releases/matte/camera.jpg)
m|3
01 January 2010, 04:08 PM
To best determine Z-distance between objects depends on how much movement you want to see when the camera dollies. If you want the background objects to move forward faster then use less z-depth. Use more z-depth if you want the background objects to remain further away. Same rule for foreground objects.

Of course, you'll have to scale objects accordingly to regain your image's original composition before camera movement.

halen
01 January 2010, 07:32 PM
To best determine Z-distance between objects depends on how much movement you want to see when the camera dollies. If you want the background objects to move forward faster then use less z-depth. Use more z-depth if you want the background objects to remain further away. Same rule for foreground objects.

That was the problem. I really would like to know what is the "right" distance to get the movement look as real as possible. If using 30mm lens, how far should I set this rock or that bush or these mountains..? I could get some visual estimate and something that looks good by trial and error and guessing, but looking for some maths, rule, tool or something to avoid that. :D

halen
01 January 2010, 09:40 AM
I mean, it might be possible to estimate size of some object in the foreground, and use it and perspective grid to calculate at least relative distanges of objects, but it sounds like a lot of work for subtle camera movement. :argh:

Maeby just throw stuff in and experiment, but if there is some easy way to get accurete, I'd appreciate it.

m|3
02 February 2010, 03:13 AM
... but looking for some maths, rule, tool or something to avoid that. :D

I'm afraid I don't know of such an equation to use to figure out the "right" distance. But you mentioned you're converting a matte painting into 2.5D space. When looking at the painting, can you not guesstimate the amount of movement you'd like to see between objects?

For example, if the painting has a mountain in the deep background that's faded (which suggest it's miles away)... then when the camera dollies that mountain should almost still be in the same location.

Are you willing to share an image of the painting with us? Perhaps then we can advise further.

In the end though unless you're matching footage where exact distances were measured and camera lens info recorded, your best bet is trial and error.

halen
02 February 2010, 07:50 AM
But you mentioned you're converting a matte painting into 2.5D space. When looking at the painting, can you not guesstimate the amount of movement you'd like to see between objects?

For example, if the painting has a mountain in the deep background that's faded (which suggest it's miles away)... then when the camera dollies that mountain should almost still be in the same location.

Yes, good estimates can be done. I just wanted to know if there is some other way. Hoping that if there would be an exact way, it would look 0,1% more real. :rolleyes:

Are you willing to share an image of the painting with us? Perhaps then we can advise further.

Yes, I'll share it when it's done, but it will take a while. I just tend to ask things before doing. :D

In the end though unless you're matching footage where exact distances were measured and camera lens info recorded, your best bet is trial and error.

Since most of the images are based on my own photos the camera lens info is recorded (and can be converted to match 35mm camera). And when not I can also give quite good estimates about that.

But it seems that I might be wasting my time, if it's usually done just by estimating. I'll use that time for polishing the painting. :D

Thank you.

sundialsvc4
02 February 2010, 02:07 AM
Obviously, the "right" answer is going to (entirely...) depend upon the depicted objects' imagined position in z-space.

Even though a set of planar inputs have no true position in "z-space," for the purposes of your movie you obviously want to maintain the illusion (for the audience...) that they do. (After all, you want to convince the audience that what they are looking at is not "a series of planar images," but (say...) "a terrifying horde of attacking Grues(!!) that the Hero will soon dispatch in one mighty stroke of his magickal sword!" :rolleyes: Or whatever...

So, there is no "right answer," except for your show. Determine what relative z-position for the various strips would make sense in whatever imaginary world you are trying to depict, and let the computer then do the math appropriately.

halen
02 February 2010, 11:36 AM
^ Thank you for your answer. You are right. It should serve the purpose. Somethimes it is just an easy starting point to get things "right" first and then adjust from there to do whatever I want.

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