weird image plane render issue

[jasonhuang1115]

Hi,

I have a scene with the render camera scaled up 100 times because the unit conversion between matchmove application and Maya scene unit.

If I set the image plane Depth (under the Placement) below a certain value (in my particular scene the value is around 80), a weird clipping plane will prevent the scene model (a head) being rendered. I am pretty sure the image plane is still far behind the model and my camera far clip plane is far enough. I verify this weird issue by switching the renderer to mental ray and the head renders just fine (I apply a lambert shader to the head so both MR and Vray can render it). I have a scene that can upload for anyone to investigate the issue but I couldn't figure out how to upload the .mb file as an attachment.
(I am using build 12435, the official RT build found in the website Downloads, on Maya 2011 WinXP x64)


Thanks,
Jason

[mr furious]

i don't have maya vray open in front of me... but in my experience scaling camera are always bad. try baking out the new scaled up camera into world space so that your scale factor is 1... and give it a whirl. hopefully it will help.

A

[jasonhuang1115]

Thanks for the advice. Indeed, scaled camera brought me some troubles before, too. Would you mind sharing how to bake the camera animatioin (path) into world space so I can apply that to a newly created scale-factor-1 camera?

-Jason

[vlado]

Jason, you can send us the file to vraymaya@chaosgroup.com and we'll check out what's wrong. A scaled camera might be the issue indeed.

Best regards,
Vlado

[jasonhuang1115]

Hi, Vlado,

I already sent the file to the email address above yesterday not too long after I posted in the forum. Hope to hear back soon.

Thanks,
Jason

[mr furious]

I simply duplicate my camera. zero out any transformations and scale. parent, or point and orient constrain it to the origional camera. (make sure you new camera is outside of any groups or hierarchy). Once constrained goto Keys>modify>bake simulation. This will bake the animation to keys for every from on your new camera. Delete constraints, delete original, camera.copy any FOV animation to the new camera.

also as a note you may get keys that are 180 degrees off (gimbal flipping) select all keys and right click curver>euler will fix that. and then set all your keys to spline (default state is flat and that can cause jittering on your camera move)

done and done.

[jasonhuang1115]

Great! Thanks for the tips, Andy. My original camera (scale 1) is actually under a group and that group has the 100 scale which makes my original camera a gigantic one. Hope that won't affect the workflow you mentioned.

-Jason

[mr furious]

exactly... you need to have no scale anywhere above the camera... this will bake it out into world space.

[Zdravko]

The issue was due to the "Depth" value of the Image plane which was set to 80 instead of the default 100.
The scaled camera clipping plane appears to be far back behind because of the scaling. The distance form the camera to the head is about 80 units and that is why a value lower than 90 can cause such issues.
You can easily check the distance by using the distance measurement tool.

[jasonhuang1115]

Thanks for the replay. Setting the image plane depth to 100 does solve the issue. But what I also wondered was even with the image plane set to 80, the image plane is "visually" behind the render subject (as shown in the viewport) and should not "cut" or even "occlude" the character. I guess it has something to do witht the 100x scale up of the camera.

[Zdravko]

The issue was due to the "Depth" value of the Image plane which was set to 80 instead of the default 100.
The scaled camera clipping plane appears to be far back behind because of the scaling. The distance form the camera to the head is about 80 units and that is why a value lower than 90 can cause such issues.
You can easily check the distance by using the distance measurement tool.

I updated my thread after you post yours.

[jasonhuang1115]

I see. Thanks for the update. So if I understand correctly, on the scaled camera the near clipping plane is also scaled which caused the issue.