>From your description, I was expecting to see something dramatic, but this is 
>pretty subtle.  Loading both geometries in ParaView, it looks like car 0 is 
>slightly longer than car 1.  When you set the camera in ParaView directly, you 
>see this.

I think the problem with your script is that you are calling view.ResetCamera() 
after setting up the camera.  ResetCamera will dolly the camera to "fit" the 
geometry in the view.  So for the smaller car the camera will zoom in a bit to 
make its bounds fill roughly the same space as the larger car.  Consequently, 
the python-generated image of car 1 makes it look bigger.

For the python-generated images, the cars are actually about the same size in 
the image.  I measured them both to be about 18 pixels from the left of the 
images and 31 pixels from the right.  Car 1 might look a bit bigger because its 
boxier shape fills its bounds more.

-Ken


On 6/27/09 9:28 AM, "David Doria" <[email protected]> wrote:

(Demo files are available here: http://www.rpi.edu/~doriad/Cars/ )

If I load 0.vtp and 1.vtp in paraview, set the camera focal point to (0,0,0), 
the camera position to (20, -20, 5), and the viewing angle to 45, the car in 
0.vtp looks "bigger" than the car in 1.vtp. However, if I run the script 
CreateThumbnails.py (in the above link) with these commands

./CreateThumbnails.py --input=0.vtp --rep=Surface --output=python_0.png 
--campos=20 -20 5
./CreateThumbnails.py --input=1.vtp --rep=Surface --output=python_1.png 
--campos=20 -20 5

in the resulting images car 1 looks bigger than car 0!! Is this some 
perspective projection illusion? Or am I missing a camera parameter in the 
script that is making it look different? I feel like I may be doing something 
wrong in the script because if I run this command

./CreateThumbnails.py --input=1.vtp --rep=Surface --output=1test.png --campos=1 
-1 .25

(the difference is that campos is scaled), the exact same image is produced (as 
python_1.png).  It seems like this one should be a zoomed in version as the 
camera should be very close to the car.

Any thoughts?

Thanks,

David



   ****      Kenneth Moreland
    ***      Sandia National Laboratories
***********
*** *** ***  email: [email protected]
**  ***  **  phone: (505) 844-8919
    ***      web:   http://www.cs.unm.edu/~kmorel

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