The "Valid boundary not found" error message may display when you try to generate a 2D or extruded 3D space from your model.
Some objects that are needed to create a closed boundary for the space are either not valid boundary objects for spaces or their Bound Spaces property is set to No. To see all objects that are currently boundary objects for spaces, click
. If an object that is needed for the boundary does not display, it is either not a valid boundary object or its Bound Spaces property is set to No.When you generate a 2D or extruded 3D space, you can define an allowed gap size between colinear boundary objects. If the colinear gaps in your model are larger than the allowed gap size, the model is considered not closed, and a space cannot be generated or might flow into an adjacent area. In that case, change the maximum gap size to a value greater than your largest colinear gaps.