Match resolution gate (overscan) and final render

[SreckoM]

How can I match render output with resolution gate? Here is example of viewport with resolution gate and what I get on render.
http://screencast.com/t/ODA2Zjkx
Film resolution gate is set to overscan. What am I doing wrong?

[Reaversword]

Interesting... I want know it too.

[pechart]

Do you use the vrayPhysicalCamera? If so, make sure that the focal length of the maya camera matches the vray one. The standart for the maya cam is 35mm, for vray it's 36mm. I guess the maya viewport resolutiongate is drawn accordingly to the maya cam, not the vray cam.

[mr furious]

there could be a bunch of things going on. I'm going to assume that your using a standard maya camera. The first rule (in any render) is to set your cameras vertical and horizontal aperture to match a desired "real" world camera. A good google search will give you some standard film camera aperture sizes.

Also it is important to know that maya's camera aperture is ALWAYS in decimal inches (doesn't matter what you set your units to). I don't have maya open in front of me ... but i know the default camera is a 35 mm "still camera" (24mm x 36mm) or 0.944 x 1.417 which is the aperture size in decimal inches (sound familiar?) The camera's aspect ration is derived by dividing the horizontal aperture by the vertical aperture (36/24 = 1.5). That is your camera's aspect ratio. The next important thing is that your camera's aspect ration MUST match the output resolutions aspect ratio otherwise your image will be artificially distorted into the output size. So to get an predictable FOV output with maya's standard camera you must have a resolution 1080 x 720 (1080/720 = 1.5 your aspect rato)

So to get your film gate to match your resolution gate, you need to match your aspect ratio of the camera aperture to the aspect ratio of your image output.

A full frame HD camera (Sony F35) sensor size is .980" x .551" (aspect ration of 1.77 and the standard HD resolution of 1280 x 720 (aspect ratio of 1.77. Punch those numbers in and you'll not only get accurate lensing information but you'll also have a matching resolution and film gate in Maya (or any other package).

Just remember when going to nuke or other packages like max they use different units (mm) and max only exposes one part of the aperture and derive the vertical aperture by using the aspect ratio. Nuke and Max uses mm so you may need to convert your decimal inches to mm in order to get your nuke camera to match your maya camera's FOV.

Again, I don't have the physical camera settings in front of me...but if you do the math right... and set your output image size (and ratio) to match your camera aperture ratio... you'll get what you expect.

I hope this answers your question.

[mr furious]

SreckoM looking at your posted jpg. I'm guessing your showing the "film" gate. if you turn on the resolution gate... that would match the crop in your rendered output.

[SreckoM]

As a matter a fact it is resolution gate at image I posted. Final render is closer to film gate but it is not 100% film gate too.
I can not match film gate and resolution gate, because when physical camera attribute is activated for camera, 'Film aspect ratio' is 1 and can not be changed.

The best match I get is to put 'Fit resolution gate' to Fill.

[pechart]

Did you try to match the focallength of the physcam and the mayacam? I had that problem and this was the solution.

[SreckoM]

I can not do that. Standard camera focal length is driven by physical camera focal length, so value can not be changed.
Can you change mayacam focal length when you have physical camera attribute activated?

[pechart]

Uhm... Now that you say it i'm not sure.
I'm not at my workstation now, but i remember, that i had a problem with that, because vray changes the focallength to 36 by default and when switching between those two i ran into trouble. Hmm.