First, we want to import the camera tracking data we exported in the last part of this tutorial into 3dsMax. The file we exported is a .ms file and you can import it by simply dragging it into one of the viewports in 3dsMax and selecting 'Open File' from the context menu.
Ensure that the length of your animation in 3dsMax matches the number of frames in the composition in After Effects. If you have a mismatch, the rendered elements might not fit properly onto your original footage. The UFO clip I exported had 240 frames and my 3dsMax project has been set to the same number when I imported the .ms camera data.
A new camera and one dummy object for each null object we exported from After Effects will appear. Note that the camera is aiming downwards, which does not really match the way we filmed the scene. This is happening because After Effects and 3dsMax use different coordinate systems. This is the left viewport in 3dsMax.
Again, if you have vRay, it might be worth switching out the generic camera for a vRayPhysicalCam because it has a lot more things you can configure. I assume that if you are using vRay you will know how to do that anyways
Let's fix up the fact that the camera is pointing downwards at the ground.
Select the camera and all the dummy objects in the scene and group them together.
Now rotate the group by 90 degrees to have the camera face the correct way. Do not ungroup the elements or their relative positions and keyframes might get misaligned!
Now select your perspective viewport and set it to show the view of the camera.
If you play back your animation now, the camera should execute the same motion as the camera we created in After Effects. It should match up with the movements of your real life camera from when you filmed your footage.
All the null objects should move exactly like they did in After Effects.
If your null objects do not move exactly the same way they did in After Effects, something might have gone wrong in the process and you will have to figure out where things went wrong. Once they match the clip in After Effects precisely we're ready to create our 3D elements.
However, before we get to that, let us set up the background of the viewport for the camera to use our original footage. This way we can see how the null objects and any 3D objects we create will sit in our original scene.