I have a unique scene that I am attempting to solve for motion. It is some aerial footage of a camera following a moving train along a track. The camera is basically flying alongside the train from a distance. I was able to solve the camera motion correctly, and the 3D camera moves along the expected path. However, when I add an object to solve for and track the train, the solved object just floats in 3D space much farther out than where the object should be and it doens't move along the "landscape" at all.

Obviously to the viewer the train is moving across the landscape with the camera, but the tracked points all stay basically in place and this throws off the solver.

Is there a way to help Blender correctly place this object and solve for it? Without correct motion I can not, for example, add physically moving smoke to the train.

Edit: Some people have asked me to provide a link to the video and while I cannot provide the exact client video, from 2:45 to 2:50 in this video is the identical motion.

  • $\begingroup$ @cegaton You mean the train? Yes it is, and that's part of the difficulty I believe. $\endgroup$ – CGEffex Jul 10 '18 at 16:23
  • $\begingroup$ @cegaton I added a link in my original question $\endgroup$ – CGEffex Jul 10 '18 at 18:52
  • $\begingroup$ If you have succesfully tracked the landscape (with an error 0.3 or less), then you must have some solid representation of the landscape or terrain. One solution I can think of is to combine 2d tracking with 3d. Pick a single point on the train and track it. Then link that to an empty. The empty will move correctly across the screen even though it will not correspond to anything in the 3d space. Create your smoke emitter and place it roughly on the landscape in the 3d scene, then parent the emitter to the empty (keeping the offset) so that the empty provides the motion for the smoke emission. $\endgroup$ – user1853 Jul 10 '18 at 19:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.