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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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 Posted: Tue Mar 06, 2012 1:18 pm Post subject: Lightwave model is sliding quite noticably in Layout |
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| I did a solve for the camera on the often used flyover sequence of a construction site and exported to Lightwave Scene. I loaded the scene in LW 9.6 and copied the focal length of the lens to the camera in LW. The trackers look pretty rock steady in SE but in LW (along with any models I put in the scene) are sliding around quite noticably. The camera is about 87m above the ground and the CG objects look like they are sliding around at leas a meter. The solve error is sub-pixel but the sliding appears to be several pixels wide. Has any had this experience and know how what is causing this problem? |
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borgus
Joined: 30 Dec 2009
Posts: 144
Location: bremen, germany
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| Posted: Tue Mar 06, 2012 1:43 pm Post subject: |
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hi!
you can test your solve when you place a test object like a box or
your model directly onto a tracker. If the sliding is gone you probably
just placed your object somewhere above or below the calculated ground/plane. |
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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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| Posted: Tue Mar 06, 2012 9:38 pm Post subject: |
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| The object is sitting right on top of the XZ plane. I was very aware of that because the manual says that it is the most common cause for sliding. But I am convinced that it is not the cause of the sliding I am seeing in lightwave. I exported my object to a DXF file so that I could import it into SynthEyes to see if I could reproduce the problem there. Importing the DXF causes SE to crash so I was unable to do the test. |
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borgus
Joined: 30 Dec 2009
Posts: 144
Location: bremen, germany
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| Posted: Wed Mar 07, 2012 3:42 am Post subject: |
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dxf? what's that ?  you can't just take any export format and re-import
it into SE, it doesn't work like that...
you said you copied the focal length animation to the camera, where
did you get it from? When you just use a camera from LW you probably
don't have the same filmback. |
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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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| Posted: Wed Mar 07, 2012 9:12 pm Post subject: |
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| borgus wrote: | | dxf? what's that ? |
I am impressed with the number of formats that SynthEyes will export to. I am not so impressed by the few options there are for importing objects. Obviously it is because SE is not intended to be used to do much of anything but tracking so exporting is far more important than importing. Go to Import>Mesh then select one of only two formats that are in the file navigator popup. They are: 1) Wavefront OBJ File and 2) DXF File. DXF is an AutoCAD format that is often used for 3D object interchange. In fact it stands for "Drawing Interchange Format". It just occured to me that Lightwave used to be called Wavefront. That OBJ import format must be an old LW format.
| borgus wrote: | | you said you copied the focal length animation to the camera, wheredid you get it from? |
It is near the top of the lens panel just below "Field of View". It is a little puzzling to me that SE can come up with a focal length during a solve. It seems to me that this is something that you would have to manually enter into SE. But the number is there and the shot list I fed it almost certainly doesn't explicity tell SE when the focal length of the camera lens was. Perhaps it is just a default "guess" to have something there instead of nothing.
| borgus wrote: | When you just use a camera from LW you probably
don't have the same filmback. |
That sounds like my line of reasoning. Doesn't the focal length plus the resolution pretty much dictate what that would be? Or is there yet another parameter I need to feed to LW? |
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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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| Posted: Wed Mar 07, 2012 9:32 pm Post subject: |
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| I guess "slide" is not the correct term for what I am observing. If the object was not at the level of the terrain in the video then I would expect that paralax would cause a more or less continuous drift of the object (in a straight line)from where it started given that the camera is moving at a constant rate along a straight line. What I am observing is more like "Brownian Motion" in that the object is vibrating around a point much like an electron would travel around a nucleus instead of staying fixed relative to the background image. Because of this I am certain that my problem is not caused by placing the object at the wrong level. |
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The Happy Friar
Joined: 29 Mar 2011
Posts: 102
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| Posted: Thu Mar 08, 2012 6:32 pm Post subject: |
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| Posting a video of what you're seeing might be the easiest way for someone to help. |
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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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PabloMack
Joined: 06 Jan 2011
Posts: 15
Location: Houston, Texas USA
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| Posted: Fri Mar 09, 2012 12:23 pm Post subject: |
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| One thing I tried is to shift the frames so that the first frame is frame 1 instead of frame 0. This seems to have improved the jitter noticably but I can't tell if it is optimal. I looked closely at all six path variables and they are pretty atrocious, not doubt, because the camera was hand-held and not very well stablized. The Y Position looks almost like a saw-tooth while the Pitch and Bank variables look pretty brutal. It seems obvious that using a stablized camera from the beginning would have improved things considerably down the pipeline. However, such hand-held shots do have their artistic appeal for many situations. |
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