Checking a Calibration inside a Render Engine
Warning
the following needs a working render engine and tracking system
1. Setup the project
In EZprofile, export the calibration for the target render engine.
In the engine, load the exported lens file and set up a project in which you can overlay AR on real footage. Place a test object in the real scene and match
it with a virtual object.
2. Field of View
Center the object in the middle of the frame. Move the zoom and focus without moving the camera, especially around the eventual outliers identified in EZprofile, see if there is pumping between the real and virtual objects.
If you have not calibrated the tracking delay yet, you can do this by steps, that is move the lens control, wait until the video and AR catch each other, and compare if the real and virtual objects are still aligned.
If a point is problematic, you can manually modify the camera focal length in the engine until the objects match again, write it down, and then modify the corresponding row in the Raw Data Table using the formula:
3. Distortion
Once the FOV looks good in the center you can check distortion in a similar way to FOV, but on the side of the frame where the distortion has the largest effect.
4. Nodal Offset
For nodal offset this is more tricky, since an issue in the tracking can hide an issue in nodal offset. Start by doing the tracking lineup carefully (if you use EZtrack, follow this procedure : Advanced Lineup Video Tutorial). Then you can go on a point where you are confident in the nodal offset calibration and fine-tune the tracking front offset there. Finally, move the zoom and focus around to see if the tracking front offset is compatible with the rest of the nodal offset calibration and check if there are problematic points.
As for FOV, you can correct a wrong point in EZprofile by going to the same zoom and focus values while in the render engine, adjusting a manual front offset until it works and then go back in EZprofile to change the nodal offset value at that point using: