You have an intermediate image plane so the sign was changed. Your system has positive power so don’t worry.

REAY should work good there. What message did you get?

@Andrey.Pravdivtsev 

Thanks, Andrey.

1. I’m going to find the relationship between the focal length sign and the intermediate image.

       Opticstudio usermanual doesn’t have the convetion, maybe you can recommend a book              which I can read.  

       2. As for the REAY operand, see the picture below

    because of the catadioptric structure, rays reflect at the surf38 first and then pass through the surf38 , the REAY operand tells the refraction position only.  How can it tell the reflection position also? Should a dummy surface be involved,I guess?

Hi,

1. It can be internal Zemax sign convention. Sign change every time you have an intermediate imape plane. Or you can look on the sign of max field point.
2. Yes, you are correct, you need to set a surface there. For a design with a mirror in sequentional mode it is common to have several components for the same surface (for example Mangin mirror).