BSPs get deleted when converting to static Mesh

Hey there.
When I convert a collection of BSPs to Static Meshes which contain Subtractive BSPs,
the BSP altogether get deleted.
However, atleast the Subtractive BSPs should stay because they are used for connections like Doorframes and Tunnels.That means If I convert one “BSP Room” into a static Mesh, the other BSP Rooms do not have a door frame anymore for example.

Hey Raildex_,

I just tested this on my end in a new blank project and did not get the same results. I believe you are overlooking an important step when converting BSP’s to Static Meshes.

You want to make sure you are selecting the Additive and Subtractive brushes, then setting the actor’s solidity to Solid. Then Convert to Static Mesh. I just ran a test and created a box with a number of various holes representing windows and doors of different sizes. It worked fine on my end.

Let me know if you have further questions.


Place 2 Additive Boxes next to each other.
Connect them with 1 Subtractive Box.

Convert Box 1 and Subtractive Box to Static Mesh

Observe how both the Additive Box and Subtractive Box disappear and get replaced by the static Mesh. The other Box loses the “hole”.

This is expected. If you do not select all of the actors utilizing the subtractive brush, as well as the subtractive brush, it will not convert as you are anticipating.

Did you read my directions on how I explained the process of converting your BSP’s to Static Meshes?

Thank you,


I see. I used a single Subtractive BSP to connect different rooms, which deletes the connection of one room when converting one room to a Static Mesh.
However, using two subtractives solves this of course.

Although I think that an option to delete/remain the BSPs that should be converted would be nice nonetheless.