Artifact with Tweening

Hi: A bizarre artifact is appearing when tweeting a rectangle–one corner of the rectangle extends (or bubbles) out during the tween, but is not visible at the beginning or end of the animation. It does not appear to be editable. It is recurring repeatedly – see attached file. Driving me crazy. Thanks for any help. Dave S.

Rectangle with artifact.sifz (5.1 KB)

Don’t use “Insert/Remove item” in the animation mode - it often produces weird effects like you mentioned and I don’t know if it’s a bug or intentional.

Just construct your shape from 6 vertexes from the beginning and then animate it.

Yes, you were correct – I was using Insert / Remove Item and Keep Shape. This resulted in weird effects, including an artifact in one corner; the glitch appears in the past and future despite keyframes without leaving waypoints. Using 6 vertexes from the beginning is working so far. Thanks. Dave s.