Camera Proj Persp to models

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Old 10 October 2012   #1
Camera Proj Persp to models

Hi all,

I have done some camera projection of a still image and projected it into maya.
After getting my perspective right (learned from the techniques that are taught by Digital Tutors), I tried to model out one of the builings in full details.

First I am not sure if I am doing it the right way, because after my modelling, I found out that my building is not symmetrical in a sense.

I have uploaded 2 images, you can clearly see that on the right side, the curve of the building is not conforming to the curve as seen in the image.

And so, I would like to know if:
1. is this a common occurence for camera projection?
2. perhaps my persp (match-moving) still needs more refinement?
3. prior to qns 1, is it right for me to manually move the vertices so as to get the structure of the building?
4. lastly, is it a necessary factor to model it as detailed as possible for camera projection?

Many thanks in advance!

Below are the images:




 
Old 10 October 2012   #2
If you know for sure that the real building has simmetry, and the 3D model you're having hasn't ... it's probably a problem related to yourf camera settings like lens,position or filmback.

One of the great advantages of projecting ... is that you don't need to model details ... unless you need them. If the building has no elements emerging from the main body that can create parallax if the camera moves, cast shadows or catch reflections, there's no need to model details. In your case I'd probably model only the big yellow sign, and maybe (I don't know what you are going to do with this model), add some detail on windows if there's need to catch some shadows. The reflexion of the windows can be perfectly done with a texture.

I hope this helps.

Lluis
 
Old 10 October 2012   #3
Originally Posted by Cuni: If you know for sure that the real building has simmetry, and the 3D model you're having hasn't ... it's probably a problem related to yourf camera settings like lens,position or filmback.

One of the great advantages of projecting ... is that you don't need to model details ... unless you need them. If the building has no elements emerging from the main body that can create parallax if the camera moves, cast shadows or catch reflections, there's no need to model details. In your case I'd probably model only the big yellow sign, and maybe (I don't know what you are going to do with this model), add some detail on windows if there's need to catch some shadows. The reflexion of the windows can be perfectly done with a texture.

I hope this helps.

Lluis


Hi Lluis, thank you for your prompt reply. Greatly appreciate it.

Pertaining to the first part of the info you have provided, I have a few questions to ask.

First, as I am going to render it out in HD1080 (have set it in the render settings, image-wise is also in the dimension of 1920x1080), the following are in regards to my render camera:
1. do I have to recalculate the Film Aspect Ratio?
Though the default values initially is 1.50, I have changed it to 1.78 (having 1920 divide by 1080), as such is it correct for me to do so?
2. For the 'Fit Resolution Gate', I have changed it to Overscan instead of Fill. Will this affects my positioning of camera as my image itself fits to the HD1080 dimension?
3. Lastly, the attributes for Image Plane, I have set the Fit to Fill, however, I am not sure if I should click on the option - Fit to Resolution/Film Gate, as I am seeing little to no change though my camera.

Secondly, I wanted to model it out in detailed is because I will want to implement some dynamics factor into my scene.
On the other hand, just like to know, if my projected objects belongs to the BG (in the image),
for the symmetry part, do I need to be so anal about it?

Looking forward to hear from you soon!
 
Old 10 October 2012   #4
I'm glad my ideas helped.
About your camera, the ideal would be to have the size of the camera's sensor, but I think your numbers can work. Your imageplane should match perfectly your film gate, whatever parameter you use. The best way to know that is rendering your 3D and do a quick over in your compositing software, and it should look like in your viewport.
In realistic visual effects it always work, lets say, the closer you go to the real thing the better it looks. But obviously cheating is allowed, specially if it works and there's no time. So, if it works for you and the customer, is fine.

Good luck!

Lluis
 
Old 10 October 2012   #5
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