Maya units and vray's physical camera DOF

[wizzackr]

Hi there.
Correct me if I'm wrong here, but from my testing the depth of field settings in vray's physical camera seem to rely on Maya being set up such that one unit = cm. Now for smaller scenes this is no problem, obviously, but for larger ones it is rather unpractical - eventually vray will start throwing warnings about the scene bounding box being too big if we're talking city parts/landscapes etc. My question therefore is, if there is a way to have vray compute DOF depending on maya's scene unit setup (meters for example), a global multiplier or something similar.
Thx, J

[smbell]

Maya's units are truly useless and cause more trouble than they are really worth. They are best left at cm for not only vray, but just about every thing else in maya. Depending on the scene type, outdoor, indoor, etc, we (and just about everyone else I know) pretend that a cm is a foot or 5 feet or whatever we need to do to keep the scene size in check. for most outdoor large scale scenes, we do 1cm = 10 feet.

[wizzackr]

Hey smbell - sure, that's how we handle it as well - but the Problem then is, that vray's physical camera settings for correct DOF will not work (or am I not getting something here??). For example: Setting up a scene pretending Maya is at 1 unit = 1m (ie. not changing anything in the globals) will not yield the physically correct DOF at a focal distance of now 1 unit = 1m, as vray seems to always assume the subject is 1cm away. Hence my question if there was some global multiplier to adjust that within VRay's controls (circumventing maya's own, which btw, VRay doesn't seem to respect)

[wizzackr]

Anyone? ...or am i not getting something here?

[yolov]

Sorry for the late reply, we're actually looking into this, but it will take us some time to get back to you after figuring out what's going on.

[wizzackr]

Thank you, yolov. For the record - I did not want to come across like a total Clown, just thought I was missing something super-obvious. Anyways - thanks for looking into this.

[wizzackr]

Giving this a bump - we're again in a situation where we want to precisely match Alexa footage with close to real DOF of the cineprime lens used on site and have a Maya scene in thousands of units to match a cm scale... Any way we can stay in meters (where our modellers work)?

[yolov]

There's a fix in the nightlies from Thursday - so any build from that day or later should have it. Not fully tested yet, so we're still working on that part. You can give it a try and let us know if you find more issues.

[wizzackr]

Hi Alex - thanks, just having a look right now. How did you implement it - setting maya scene units to meters should do the trick?

[yolov]

I think there were some conversions that we didn't do properly, but I'm not 100% sure and I need to check.

[wizzackr]

nice - now we have a maya problem: If we turn the units from cm to m in the globals the DOF seems to match our plate (yay), but our model is now 0,2m instead of 20 meters (but modelled in cm space in Maya units) before. So while the DOF seems to work we now run into rounding errors all the time modelling because of the 0,000 cutoff. So: Ideally we'd have a multiplier or so in the physical camera settings so Maya's wonky unit system can stay as is (also to prevent RBD screw-ups!) and the DOF renders correctly...

[seandunderdale]

Ive been having the same issue lately. Been triyng to work with real world geo for mountain backgrounds at a km scale, and having my DOF appear less than what Id get for a car interior. My close to camera object is a meter away, and the mountains 1km, and there seems to be little or no DOF. I have to go down to F numbers of 1.0 to get anything at all. I see the zoom factor allows the user to multiply the DOF effect, but is this the best way to work? I have tried Vray Next and 3.6 in the last two days and had similar results.

I tried making my scene scale in cm and meters and had the same issue. Ive tested in both Maya 2018 and 2019.

[damaggio]

It's also important to scale your camera correctly Object Display >Locator Scale....just to make sure, do not scale camera with scale tool.

[seandunderdale]

The camera hasnt been scaled, so I dont think that its contributing to the problem.

[damaggio]

wonder how you folks resolved this issue.....