Element 3D with Camera Track Issue

[Isllhomz]

Hey all...I'm kind of frustrated with an issue I'm having and hoping someone here can help!

I'm doing a scene with a 3D .obj file imported through Videocopilots Element 3D.

When I track the 3D camera for the scene, and place the element in the 3D space, I get weird movement, rather than having it stuck on a point like a solid or a null object.

I can't figure out why it's not tracking the same way?

I'm not sure if I'm being clear, so I've posted a screen recording of what is happening.

HELP!!

[RobShultz]

You might want to try selecting the solid in the timeline and then dragging the hammer from the project panel onto the solid while holding option on Mac or alt on Windows. Release the mouse first the hammer should replace the track solid and stick to the scene.

[Rick Gerard · Accepted solution]

Element 3D uses the comp center as its center point.

Camera Tracker sets the origin at 0, 0 instead of comp center. Getting things set up correctly is pretty straightforward. You have to reset the track to the comp center. Here is the workflow.

When Camera Tracker has finished solving the camera, pick several points on a planar surface that can act as the origin and ground plane. If the perspective on the target looks correct, use those points to set the Origin and Ground Plane. Immediately create a Camera and a Solid using the same target. That will ensure that the camera is right side up and everything on that frame is working correctly. Adding a comp or layer marker on that frame is also a very good idea.

I usually add a Grid to the Solid and verify that the camera track is accurate. If everything looks correct, scrub through the footage and find the place in the shot where you want to add your 3D object. Ensure all the Track Points you select are on a common plane (surface). Then add another solid. I never use nulls and seldom add text because you cannot see if the nulls are tracking properly, and it's easy to put a text layer in the same position as a solid. I also usually set all of the Track Solids as guide layers. 

When you have verified that all your Track Solids are in the right place, add a new 3D null to the Comp and set the null's position to 0, 0, 0. Move to the marker if you have added it to the comp. Parent all of the 3D layers to the null. Now reset the position of the null to comp center by resetting the null's position property.

Your camera track is now centered at the comp center. You can then release the parent. You can now add a solid, apply Element 3D to the layer, and insert your 3D object.

From there, is it easy to position the 3D element where it needs to be because the layer position of the reference solid (track solid guide layer) is now based on comp center instead of 0, 0, 0. 

If you do not set an Origin and Ground Plane and you don't make sure that your track solids are properly attached to a surface in the shot, it is nearly impossible to properly line up a 3D object in your shot. This workflow makes if fairly straight forward using any plugin that will let you add 3D objects to an AE comp.

There was a script that automated this process, but I have lost the link for it and can't find it. If I locate it I'll post a follow-up.

Edit: Found it. It's called Normalize Tracker and there is even a video explaining how it works.

[Isllhomz]

Wow Rick...thanks so much. Conveniently I had the Normalize Tracker script downloaded from a previous issue, but never thought to use it. I really appreciate the time you took to lay out the answer and workflow.