Some parts are not visible in the rotation movement

[bibasaktanesi]

Hey hi hope you are well!

In my Modelviewer work, the parts I show in the picture become invisible while rotating. How can I fix this problem?

1 right
2 does not appear

[elalish]

This looks like a z-order problem for transparent materials. It shouldn't be a problem if you have only one transparent mesh; is it possible you have BLEND or MASK mode set on objects that should be OPAQUE?