Fusing scan make it different shape?

Hi im new with all this and sorry for my english, im not a nativ speaker. i scanned my van (i know it has holes,for me fine enough for what i need) and got to the point when i wanna merge 2 scans cuz i coudnt do van inside with one take. Revo scan manual said i need to fuse scans first. I tried to do it but after fusion it looks not like what i have scaned. Can anyone tell me why it creates this rather to keep shape i scanned? How i should fuse it to be able tto keep shape and then merge it?

device :Miraco,

i used markers, revo scan on PC
my raw scan 1:


fused:

Hi @CuteNekoPie

Please contact customer@revopoint3d.com and send them zipped project files for investigation , they will help you out with this issue , you can include the link to this thread as reference.

In the future don’t scan that big areas at once , you need to have not bigger section like 1-2 m maximum to preserve the accuracy better