Imported models not aligning with backplate

Hi,

I am having trouble aligning 3D objects where they should be in relation to my imported camera. As you can see with the 3D model of the building below: it is not aligned with the backplate, even though all of the settings are the same (backplate resolution, model scaling, etc.), it always seems to be just slightly off.

This seems to happen with most of my projects when the camera has been imported from a motion tracking scene in Blender, as you can see below with this model of a car I imported, which again was perfectly aligned in Blender (left), but is slightly off in EmberGen right) - and this is on frame 1.

I have set all object animation overrides to 60fps and my backplate frame rate also. I am wondering if it has something to do with the origin points, FBX scaling, or the way EmberGen handles imported camera data, such as focal length, sensor fit, etc.?

I just can’t figure it out, and would really appreciate some help!

Tom

Hi Thomas, Sorry about this, I’m not sure what the issue would be here… Can you send these files to us? You can upload a google drive folder here or send it to us at support@jangafx.com!

Just to note it here. Will (I think) from JangaFX responded to my email with the solution:

When doing a camera solve in Blender, if you keep ‘Optical Center’, ‘Focal Length’ and ‘Radial Distortion’ deselected, you will NOT have this problem.

deselect_these

Blender alters the ‘Camera shift’ X & Y values to account for (I think) this Optical Center refinement, and these values are currently not handles by EmberGen:

cam_shift

I also keep focal length deselected just to be sure, but I’m not sure if that is necessary. I have since imported the camera (with no camera shift) and it matches up PERFECTLY.

Thanks Will! (?)

Yep that was me! For others who have this problem make sure you zero out these values. From my research it didn’t seem that Unreal Engine could detect those parameters either.

1 Like