public void DrawSolid(Graphics.Graphics graphics, Solid solid, Color color, bool textured = false)
        {
            // extract triangles from faces
            // trianglefan to trianglelist
            foreach (SolidFace face in solid.Faces)
            {
                if (face.Indices.Count < 3)
                {
                    continue;
                }

                SolidVertex[] vertices = solid.GetVerticesForFace(face);
                if (textured)
                {
                    graphics.DrawTexturedSolidPolygon(vertices, face.Normal, color, face.Texture);
                }
                else
                {
                    graphics.DrawSolidPolygon(vertices, face.Normal, color);
                }
            }
        }