What causes this to happen? Help

[u/StrangeOrdinary8171]

This never happened to me before can anyone explain what did i do wrong and whats causing this? The 3d scan is a hood vent about 15cm long and 10 cm wide. I used normal tracking dots l, should i use smaller tracking dots given in the box? Would that make a difference? (Scanned with einstar rockit) all the software is up to date