public enum Object3DRenderingMode : System.Enum, System.IComparable, System.IConvertible, System.IFormattable  

//var bsl = ...;
//Note: wire_frame_filters can be null in this example
var wire_frame_filters = bsl.GetFilters().Where(
  f => f.FilterBlockDefinitions.Any(
    fb => fb.FilterBlockMode == Object3DRenderingMode.Wireframe));
//substitute Object3DRenderingMode.None to get blocks with a solid mode (default)
//and...
//fb.FilterBlockMode == Object3DRenderingMode.Wireframe &&
//fb.FilterBlockMode == Object3DRenderingMode.None
//for blocks with both

//Must be called on the MCT
//Assuming retrieve filter ok
//var bsl = ...;
//var filter1 = bsl.GetFilter(...);

var filterBlock = new FilterBlockDefinition();
filterBlock.FilterBlockMode = Object3DRenderingMode.Wireframe;
        
var selectedValues = new Dictionary<string, List<string>>();
//We assume QueryAvailableFieldsAndValues() contains "Walls" and "Doors"
//For 'Category'
selectedValues["Category"] = new List<string>() { "Walls", "Doors" };
filterBlock.SelectedValues = selectedValues;

//Overwrite
filter1.FilterBlockDefinitions = new List<FilterBlockDefinition>() { filterBlock };
//At 2.x - bsl.SetFilter(filter1);
bsl.UpdateFilter(filter1);