Cineversity

Hi,
I’m trying to use the C4D motion tracker to link multiple tracked cameras of the same scene. However, footage doesn’t seem to load when I add more than one camera tracker in the scene. Is this a glitch on my system?

The idea is to do a survey shot using high resolution stills and load it as sequence of images and then use the constraints tags to tie it to another video based camera track. I’m not sure the constraint tags would work between different motion tracker objects as I was not successfully able to track a survey shot from still images.

I’m obviously trying to replicate a common workflow from Syntheyes and other similar dedicated motion tracking packages inside c4d as the 3D navigation and UI of C4D is much better than the majority of the dedicated 3D motion tracking packages out there.

Regards,
Ihab Ali

Hi Ihab Ali,

Yes, I see that you try something that is offered in other tracker apps. This option is not given in Cinema 4D. I might discuss below things you might know, based on your use with other tracker apps, but since we are in a forum, I need to write a little bit broader.

Survey shots are only useable as long as THE main solve is based on it. To track several sequences of footage and solve those independently will not work, using a constrain then later on to connect features. This kind of creating a connection among different features is not available in C4D. Functions as “Combine Selected Markers”, or “Coalesce Nearby Trackers” are not available in C4D.

Deleting fake/wrong features or the one with a larger error is certainly a key to get a better solve result. Similar to Clean up trackers in Syntheyes for example, but also here, to strong clean up can move the result to a more false solve, as the correct features might have been lower in numbers than the wrong ones. (Like having clouds tracked in a shot, whereby the floor was the target).

As a side note
If you shot higher resolution with the same camera, lens and the very same use of sensor area, then use those to evaluate the Lens Chart, to get an precise lens distortion. If you have a survey shot as usable sequence with those qualities, it might help to get a better idea as well of the focal length. (Never trust what is printed on them anyway, except they are INDIVIDUALLY calibrated cine-lenses, and their last service is not too long ago.
Note that lenses change when the focal point is moved. Lens charts are often too small to get what is in the practical footage. Check if the lens is breathing to get an indicator.
If you use different cameras, each camera lens, (focal point) combination needs its own lens-chart. If a zoom lens was used, the characteristics will change as well over the course of the focal length.

Sorry that I can’t offer a solution, but I hope I have saved you some time.

If you like, please feel free to suggest this feature to MAXOn
https://www.maxon.net/en-us/support/suggestions/

Happy tracking

Cheers

Fair enough, thanks for the detailed explanation. Is there a way to select features and create planes in a similar way the AfterEffects camera tracker works? I know it’s easy enough to do that with the pen tool but I was wondering if the “create plane” feature of the planar constraint can be used to define a geometry constraint as opposed to control the motion tracker orientation. The constraint tags in general seem like they only work if added to the motion or object tracker objects. I’m just trying to explore all that can be done inside C4D’s system.

Yes there is, Ihab Ali, and you’re very welcome.

Please have a look here:
https://help.maxon.net/us/#TPHCONSTRAINTPLANAR

or more precisely
https://help.maxon.net/us/#TPHCONSTRAINTPLANAR-PH_SCENE_CAL_PLANAR
Scroll down to “Create Plane”

You need three features to create a plane.

All the best

Thank you! I’m aware of this tool but I can’t use it without also setting the scene orientation. I figured one can’t use this tag multiple times for the same axis, so if I have already defined my floor plane but want to use the tag to define another coplanar surface without affecting the scene orientation it doesn’t seem to work. Again, I was just trying to see if there is a feature similar to AE’s camera tracker that allows for selection of any number of tracked and solved features to define a plane.

Ihab Ali,

Yes that would be the case, setting the orientation, if you keep the Tag.

Have a look at this 60sec clip, it explains the method of getting it anyway. Safe your scene before you do it of course.

Screen capture
https://www.amazon.com/clouddrive/share/YlpXWMGx6cau0jbqEscpBCeWQuF53Eg67lJ6g2zXRsq

Of course, any plane (or object) can be set to the position of one Tracking Null (feature) and then use the Target Tag to orient this object. Constrains will work in the same way. Once placed, the constrains are not longer needed.

See clip here:
https://www.amazon.com/clouddrive/share/l7ombGIfpIZOUtexDpQPaYe34kaaRRfjHMgF63pyRQt

… and I’m certain there are many other ways. Just let me know what you need, perhaps with a sketch or scene file, please.

All the best