PDA

View Full Version : circle created in PShop is not rotated properly in Combustion


rebrov
06-23-2004, 07:27 AM
guys,

I want to create a rotating disk in the video. the disk will be a little bit leaning and rotate in the video, with some footage showed up on it.

I created a perfect round disk in photoshop and imported into combustion. When I just rotate the disk along z-axis with some degree, it looks unpropotional, or say the disk was some how squashed.

You can check the URL to see what happened.
http://web.ics.purdue.edu/~zlu/squashed.jpg

And when I change the degree in x and y to make some leaning, and roate along z axis, which is perpendicular to the disk as I assumed, it shakes.

I can make sure the rotation axis is in the center of the disk.

The same thing happend in AE.

dg
06-23-2004, 11:28 AM
That's probably because you didn't took into account the pixel aspect ratio of your final composite when you were doing your graphics on Photoshop.

Try to set your composite to Square Pixel (just to check), or turn on the Pixel Aspect Correction (Use Aspect Ratio) on the viewports to see if the problem remains.

Which type of output will be yours?
DV NTSC, DV PAL, DV NTCS Wide, DV PAL Wide, HD, 2k, NTSC...

Each format has it's own pixel aspect ratio that you have to respect when creating graphics.

Case you use Photoshop CS it has pixel aspect ratio support and preview making it easier to do things correctly without having to bother with math.

Cheers,
dg

rebrov
06-24-2004, 06:13 AM
That's probably because you didn't took into account the pixel aspect ratio of your final composite when you were doing your graphics on Photoshop.

Try to set your composite to Square Pixel (just to check), or turn on the Pixel Aspect Correction (Use Aspect Ratio) on the viewports to see if the problem remains.

Which type of output will be yours?
DV NTSC, DV PAL, DV NTCS Wide, DV PAL Wide, HD, 2k, NTSC...

Each format has it's own pixel aspect ratio that you have to respect when creating graphics.

Case you use Photoshop CS it has pixel aspect ratio support and preview making it easier to do things correctly without having to bother with math.

Cheers,
dg

Thanks sir. I'm pretty sure I kept everything by 720*480 NTSC in both Pshop and Combustion.

The problem I feel now is the Z axis is not perpendicular to the "disk".

rebrov

dg
06-24-2004, 04:32 PM
Thanks sir. I'm pretty sure I kept everything by 720*480 NTSC in both Pshop and Combustion.
Maybe that's why is wrong, NTSC 720x480 doesn't have a square pixel ratio, and your PS graphic might have, unless you done it in PS CS with the correct pixel aspect ratio.

If your composite is 720x480 with a pixel aspect ratio of 0,9 your image in PS must be done at 648x480 and then rescaled back to 720x480, as a general rule you multiply the X value of your image by it's pixel aspect ratio (X*PAR)

720x480 (0,9) use 720 * 0,9 = 648
720x480 Widescreen (1,2) use 720 * 1,2 = 864

Otherwise all of your elements will be distorted in the output, just don't forget to scale them back to a X value of 720 when you're done.


See ya,
dg

rebrov
06-27-2004, 12:19 AM
Maybe that's why is wrong, NTSC 720x480 doesn't have a square pixel ratio, and your PS graphic might have, unless you done it in PS CS with the correct pixel aspect ratio.

If your composite is 720x480 with a pixel aspect ratio of 0,9 your image in PS must be done at 648x480 and then rescaled back to 720x480, as a general rule you multiply the X value of your image by it's pixel aspect ratio (X*PAR)

720x480 (0,9) use 720 * 0,9 = 648
720x480 Widescreen (1,2) use 720 * 1,2 = 864

Otherwise all of your elements will be distorted in the output, just don't forget to scale them back to a X value of 720 when you're done.


See ya,
dg

Dear DG,

I hope I have got what you're saying. What I tried is: I created a new disk,which is scaled by 0.9 along Y.

When I imported the disk into Combustion, (NTSC aspect ratio 0.9), the disk showed up as x:y=1:0.9 The interesting thing is : When I made the disk turned along x and y with some degree, and rotate along z, the disk won't shake back and through. And it show as the effect as I want.
When I scale the disk back to 1:1, the same problem showed up.

Also, I tried to change the aspect ratio to 1 when composting, it works perfect.

Thanks a lot.

reb

CGTalk Moderation
01-18-2006, 02:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.