Hi Ivan and all
You may have answered my question in point 1) but...
For those that know how - is it not possible to take the local matrix and
recreate the live transform (for want of a better term). Even if you have to
specify rotation order at the outset.
Or is that a pointless workflow. Sort of 'bake to world' but back in Euler. I'm
talking about doing this inside Nuke.
(It may have all been covered in previous threads or on nukepedia of course)
Howard
>________________________________
> From: Ivan Busquets <[email protected]>
>To: Nuke user discussion <[email protected]>
>Sent: Monday, 1 October 2012, 9:15
>Subject: Re: [Nuke-users] Re: Baking camera and axis animation together
>
>
>Hi Johannes,
>
>
>That's a different monster, in my opinion, which is to try and match the
>camera (and motionblur) from an existing set of renders. In this case,
>matching your renders is probably more important than a) keeping the camera
>animatable, and b) having accurate motionblur.
>
>
>If I had to guess, I'd say there's 2 possible reasons why you're getting a
>better match by setting the local_matrix directly to the one in the exr's
>metadata, instead of converting that back to Euler rotations:
>
>
>1. No way to know the original rotation order from a transformation matrix
>alone. So, if you're converting to Euler, you'd have to choose an arbitrary
>rotation order, which may or may not match the one of the original camera. Of
>course, you could have known the correct rotation order beforehand, in which
>case this shouldn't be an issue.
>
>
>2. How is your renderer (the one that produced the exrs) handling motionblur?
>Assuming you're using Renderman, is subframe MotionBlur turned on? Otherwise
>the renderer might just be doing a linear interpolation between the camera
>position/rotation at each integer frame, which is the same you'll get in Nuke
>when explicitly setting a "local_matrix".
>I'm not an expert in Renderman, though, so someone with more insight might be
>able to confirm or deny this.
>
>
>Having said that, I've used both approaches to re-create a camera from
>Renderman metadata, and I've rarely had motionblur issues with one or the
>other. The few occasions where I have found differences has always been due a
>different rotation order.
>
>
>Hope this helps.
>
>
>Cheers,
>Ivan
>
>
>
>
>
>
>
>On Mon, Oct 1, 2012 at 12:14 AM, Johannes Hezer <[email protected]>
>wrote:
>
>Hi Ivan,
>>
>>that is interesting with the motionblur.
>>In my experience sofar, when getting cameras into nuke via exrs it
was always best to use the matrix on the camera instead of
converting all back to euler values in the rotation knobs ?!
>>It was more accurate and motionblur issues were gone ?
>>I know that is not exactly what you stated but I would be
interested if you expierenced the same thing with the cam data
from exrs?
>>
>>cheers
>>
>>
>>
>>Am 10/1/12 2:22 AM, schrieb Ivan Busquets:
>>
>>Might be splitting hairs, but since this comes up every now and then, I think
>>it's worth noting that there are some important caveats to using the
>>local_matrix knob to do that for animated cameras:
>>>
>>>
>>>- You lose the ability to tweak the animation afterwards.
>>>
>>>
>>>- Inaccurate motionblur. If you bake animated transform knobs into a single
>>>animated matrix, you're effectively losing the ability to interpolate
>>>"curved" paths correctly. The matrix values will interpolate between frames,
>>>but there's no guarantee that the result of that interpolation will match
>>>the transformation you'd get by interpolating the original
>>>rotation/translation/scale values.
>>>
>>>
>>>Getting back to the use case of the original post, I would recommend keeping
>>>the two separate transforms when exporting out to Maya.
>>>For one, if you use the "forced local matrix" approach you'll have no easy
>>>way to transfer that to Maya (as in, it won't export correctly when writing
>>>an FBX file, for example).
>>>But also, if you're planning to refine animation later on, it might be
>>>easier to do so on the original transformations.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>On Sun, Sep 30, 2012 at 2:18 PM, Marten Blumen <[email protected]> wrote:
>>>
>>>Stoked, solved it. Very easy thanks to the exposed World and Local Matrix's.
>>>>
>>>>Attached is a verbose tutorial nuke script; all
instructions included in stickies. Hit me up if it needs
more work. thanks!
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>On 29 September 2012 16:08, Marten Blumen <[email protected]> wrote:
>>>>
>>>>I just retested my test and it only worked on simple setups. Probably need
>>>>expert equations to make it work properly!
>>>>>
>>>>>
>>>>>On 29 September 2012 15:39, C_Sander <[email protected]>
>>>>>wrote:
>>>>>
>>>>>I guess now would be a good time to learn expressions. I'll check that
>>>>>out, thanks!
>>>>>>
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>>>>>
>>>>
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>>>
>>>
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