X-Spline control points jumping far away from spline

Version: Version 9.0.3 build 10.g4188866cd1a0

Platform: Windows 10, Radeon VII, 64Gb Ram, i9 9900K, latest version of AE

Description: At the extents of my track, several control points on the X-pline jump far enough away that I can’t zoom out far enough to see them. This happens if I track, but also if I just reposition the spline and create a keyframe. I’ve never experienced this problem before in many years of using Mocha AE. Right now I’m working around this by converting to masks and then keyframing the last few frames on the masks in AE, so not urgent but would like to resolve this.

Having read through a similar thread, I have turned GPU processing off, and then back on again. I updated to the latest AE version. Haven’t cleared cache, but don’t think that could be related. This footage is UHD from a Sony A7S3, in MP4 format.

Steps to reproduce: Track and then reposition spline.

Expected result: Spline is repositioned

Actual Result: Some of the control points shoot off into the distance

Regression: Never experienced this before.

In these images below, I stepped back one frame and manually adjusted the X-Spline and the result was as shown in the second image.


First of all, thank you for such a detailed explanation.

This will normally happen when the tracking has distorted significantly. I can see in the second shot where the spine is distorted that you’ve lost most of the head shape.

Are you performing this track just to get the rotoscoping done?

Here are three things you can try:

  1. Track with translation, scale and rotation only. Using shear can distort the plane if the track can’t find enough detail.
  2. When you start to lose the shape, stop the track, undo the last few frames and manually adjust the shape (if you’re only using this for roto)
  3. Track using a separate layer that covers the outside of the head area, then draw your roto layer and link it to the tracking layer.

Any one of these may help alleviate the problem.

Hi Martin, thanks a lot for your response. I’ll keep trying with different approaches and see if I can find a common cause, if it happens again. I’ll update here if I figure anything out. Thanks again :slight_smile: