Create a solid block from a group of rows in AutoCAD (C #)

I am trying to make a solid 3D shape in AutoCAD programmatically. I can get a wireframe drawing shape. This is what my code is currently drawing

An object is a group of AutoCAD strings grouped together into a Group object. What I want is a method that takes a Group as an argument and turns that group into a solid structural link. Here is my attempt.

public static void DefineBlockFromGroup(Group groupToCreateBlockFrom, string blockName, Point3d origin, bool replaceChosenEntities = false)
{
    List<ObjectId> idsOfEntitiesInGroup = groupToCreateBlockFrom.GetAllEntityIds().ToList(); //Getting the entities that will be used to create the block
    CreateBlockDefinition(idsOfEntitiesInGroup, blockName, origin, replaceChosenEntities);
}

public static void CreateBlockDefinition(List<ObjectId> entities, string blockName, Point3d origin, bool replaceChosenEntities = false)
{
    BlockTableRecord record = new BlockTableRecord(); //Will become record of new block type
    ObjectId blockId = ObjectId.Null; //Will become id of new block type
    using (Transaction tr = _database.TransactionManager.StartTransaction())
    using (DocumentLock docLock = _activeDocument.LockDocument())
    {
        BlockTable bt = (BlockTable)tr.GetObject(_database.BlockTableId, OpenMode.ForRead); //Getting block table to put new record in
        bt.UpgradeOpen();
        record = new BlockTableRecord(); //New record will contain all entities which will make up the block
        record.Name = blockName; //Setting name of the block
        record.Origin = origin; //Setting origin point of the block
        bt.Add(record);
        tr.AddNewlyCreatedDBObject(record, true);
        blockId = bt[record.Name];

        tr.Commit();
    }

    //copy the select entities to block by using deepclone.
    ObjectIdCollection collection = new ObjectIdCollection(entities.ToArray());
    IdMapping mapping = new IdMapping();
    _database.DeepCloneObjects(collection, blockId, mapping, false);

    if (replaceChosenEntities)
    {
        using (Transaction tr = _database.TransactionManager.StartTransaction())
        using (DocumentLock docLock = _activeDocument.LockDocument())
        {
            Entity baseEntity = tr.GetObject(entities[0], OpenMode.ForWrite) as Entity;
            foreach (ObjectId id in entities)
            {
                EraseSingleObjectFromDrawingWithId(id);
            }
            DrawBlockFacingAPoint(record.Name, record.Origin, record.Origin, baseEntity.Layer, null);
            tr.Commit();
        }
    }
}

public static void EraseSingleObjectFromDrawingWithId(ObjectId idOfObjectToErase)
{
    // Start a transaction
    using (Transaction tr = _database.TransactionManager.StartTransaction())
    {
        DBObject objToErase = tr.GetObject(idOfObjectToErase, OpenMode.ForWrite);
        // Check to make sure a valid SelectedObject object was returned
        if (objToErase != null)
        {
            objToErase.Erase();
        }
        tr.Commit();
    }
}
public static BlockReference DrawBlockFacingAPoint(string name, Point3d position, Point3d direction, string layerToInsertOn, List<string> attributeValues = null, Distance xScale = null, Distance yScale = null, Distance zScale = null)
{
    LastPositionPoint = position;
    LastDirectionPoint = direction;
    //Creating default distances if null is passed for the scales
    if (xScale == null)
    {
        xScale = new Distance(DistanceType.Inch, 1);
    }
    if (yScale == null)
    {
        yScale = new Distance(DistanceType.Inch, 1);
    }
    if (zScale == null)
    {
        zScale = new Distance(DistanceType.Inch, 1);
    }

    ObjectId blkRecId = _generateBlockRecordId(name); //Generating ID for the block
    BlockReference blkRef = null; //Reference of the block that will be inserted

    using (Transaction tr = _database.TransactionManager.StartTransaction()) //Starting the transaction to insert the block into the drawing
    using (DocumentLock docLock = _activeDocument.LockDocument())
    {
        blkRef = new BlockReference(position, blkRecId); //Creating the block reference
        blkRef.SetDatabaseDefaults();
        blkRef.ScaleFactors = new Scale3d(xScale.Inches, yScale.Inches, zScale.Inches); //Changing the scales to what the programmer specifies
        blkRef.Layer = layerToInsertOn; //Assigning layer to draw the block on
        Point start = Point.MakePointWithInches(position.X, position.Y, position.Z); //Generating first AutoCAD point
        Point end = Point.MakePointWithInches(direction.X, direction.Y, direction.Z); //Generating second AutoCAD point
        GeometryClassLibrary.Line line = new GeometryClassLibrary.Line(start, end); //Creating a line to mirror a block over if necessary
        Angle a = new Angle(AngleType.Radian, 0); //Angle to rotate  the block by

        //Assigning angle based on direction point
        if (position.Y != direction.Y)
        {
            a = line.AngleBetween(GeometryClassLibrary.Line.XAxis);
        }
        if (direction.Y < position.Y)
        {
            blkRef.Rotation = a.Negate().GetValue(AngleType.Radian); //Allowing for rotations beyond 180 degrees
        }
        else
        {
            blkRef.Rotation = a.GetValue(AngleType.Radian);
        }

        BlockTableRecord blkTblRec = tr.GetObject(_database.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;
        blkTblRec.AppendEntity(blkRef); //Adding block referece to the block table of the drawing
        tr.AddNewlyCreatedDBObject(blkRef, true); //Adding block to the drawing

        //Assigning attributes of the block
        BlockTableRecord btr = (BlockTableRecord)tr.GetObject(blkRef.BlockTableRecord, OpenMode.ForRead);
        int attCounter = 0; //Counter to iterate through attributes
        foreach (ObjectId objId in btr) //Checking each item in the BlockReference records
        {
            DBObject obj = objId.GetObject(OpenMode.ForRead);
            if (obj is AttributeDefinition) //If the object is an attribute, update it.
            {
                AttributeDefinition ad = obj as AttributeDefinition;
                AttributeReference ar = new AttributeReference();
                ar.SetAttributeFromBlock(ad, blkRef.BlockTransform);
                ar.Position = ad.Position.TransformBy(blkRef.BlockTransform);
                try
                {
                    ar.TextString = attributeValues.ElementAt(attCounter);
                }
                catch (ArgumentNullException)
                {
                    ar.TextString = "";
                }
                catch (ArgumentOutOfRangeException)
                {
                    ar.TextString = "";
                }
                attCounter++;
                blkRef.AttributeCollection.AppendAttribute(ar);
                tr.AddNewlyCreatedDBObject(ar, true);
            }
        }
        tr.Commit();
        return blkRef;
    }
}


private static ObjectId _generateBlockRecordId(string passedBlockName)
{
    Transaction tr = _database.TransactionManager.StartTransaction();
    DocumentLock docLock = _activeDocument.LockDocument();
    using (tr)
    using (docLock)
    {
        BlockTable blkTbl = tr.GetObject(_database.BlockTableId, OpenMode.ForRead) as BlockTable;
        ObjectId blkRecId = ObjectId.Null;
        if (blkTbl.Has(passedBlockName)) //Checking if the block exists
        {
            blkRecId = blkTbl[passedBlockName]; //If it does, getting the current id
        }
        else //If it doesn't exist create one
        {
            Database blkDb = new Database(false, true);
            blkDb.ReadDwgFile(passedBlockName + ".dwg", System.IO.FileShare.Read, true, ""); //Reading block source file
            _database.Insert(passedBlockName, blkDb, true);
            blkRecId = blkTbl[passedBlockName];
        }
        return blkRecId;
    }
}

      

        
        
        
      

    

Sorry, there are so many methods. I think the problem is to draw the block, but just in case I have included all the methods involved. In any case, the methods successfully create a block definition and draw an instance of that block instead of a group of lines. The problem is that the block is still a wireframe. If anyone knows how to change this approach to draw solid blocks, I would be wickedly grateful!