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Lining up Photos and Rhino Renderings. A sticky point.

R-G-P

Hi Everyone,

This seems like something one of you must have done in the past and I'm pulling my hair out a bit. I would love some input if any of you have tried something similar.

I have a model of a building in Rhino. I am doing a redesign of a portion of it and I want to combine my renderings with real photos of the site.

In the model, I precisely set the camera to a specific location, at my eye height and with the same lens length as my camera (in this case the Lumix-LX2, 25.2mm ). I went to site, measured out my position to be precisely the same as in the model, pointed at the same target and began shooting.

back in the model or in photoshop it does not line up at all. There perspective is way off.

It should really be this simple, shouldn't it? Does anyone have ideas on where the hiccups might be? I'd really like to work this precisely in the future and I'm kind of bummed out.

Thanks in advance.

RGP

 
Aug 9, 09 7:50 pm
Carl Douglas (agfa8x)

You'll need to import your picture as a background image in your rhino viewport, and then manually tweak until it lines up right.

Aug 9, 09 11:12 pm  · 
 · 
Cacaphonous Approval Bot

I've never had a background photo where I knew the lens lengths or had more than a guesstimate of the camera position, so it'd be interesting to hear from those who have, but I will say that "It should be simple" never seems to actually be the case.

A good knowledge of perspective, of shadows, using photoshop to transform via stretch, and skew , and distort should get you there.

I don't think there are any effortless images.

Aug 10, 09 12:10 am  · 
 · 
R-G-P


Sincere thanks for the replies. Unfortunately, manual tweaking is exactly what I want to avoid. I've worked that way for a long time already . I'm now interested in something precise and repeatable.

Knowing the camera's physical position in relation to the picture plane, how high the horizon is, where the target of the photo is and the lens length should be enough to recreate the correct perspective lines--- or at least something close. But the convergence to the horizon in Rhino is just completely different.

I mean, they are the "laws" of perspective, they shouldn't be arbitrarily defined in a piece of software, so I guess I'm just curious why it would be so far off from reality.


Anyway, thanks again.

RGP





Aug 10, 09 8:03 am  · 
 · 
induct

Import it to Max and use camera points.

http://www.evermotion.org/tutorials_old/compositing/arch/

Aug 10, 09 8:06 am  · 
 · 
R-G-P

Induct,

Thanks. That led me to the Rhino version, "perspectiveMatch." Does exactly what I needed.


RGP

Aug 10, 09 8:41 am  · 
 · 
Peru

I luv ev... All
Information on focallenght, shutterspeed, aperature GPS tags + more is stored in all image files taken with a digital camera, its calld exif data. Heres a simple reader where you just drag the image into the program and get all info.
http://www.takenet.or.jp/~ryuuji/minisoft/exifread/english/download.html

Aug 10, 09 8:52 am  · 
 · 
induct

Glad it worked out. I will have to look at perspective match. It seemed like there had to be something in Rhino

Aug 10, 09 6:47 pm  · 
 · 
Antisthenes

walkabout and lookabout toolbars also help to tweak it slightly if you dont get a perfect perspective match and of course changing camera lens

Aug 10, 09 8:09 pm  · 
 · 
Ian & Jonas

Rhino denotes its focal length in 25mm equivalent. The camera you used has a different sized sensor, and therefore you need to apply a multiplication factor to your focal length - in this case I think the actual focal length to use in rhino would be 112mm (25.2 is max focal length for your camera - 112mm is the max stated 35mm equivalent focal length for your camera.)

Aug 11, 09 2:42 am  · 
 · 

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