Solids and cavities in architecture 

Architecture is the art of playing with solids and cavities otherwise called forms and spaces.

Th forms enclose and form the spaces that we live in. According to the function and structure (material) of the building,form and space are different.(example : it is quite similar to the glasses we use in our life,or other equipments. Architectural space is formed from the relationship between objects and boundaries and forme planes which define limits. Those limits may be  less or more explicit, constitute continuous surfaces forming an uninterrupted boundary, or constitute only a few cues to perceive the space.

Horizontal elements:

a)base plane-horizontal plane lying on a floor and defines a simple field of space.

b)elevated base plane-horizontal plane elevated above the ground plane,visual along its edges reinforce the visual separation between its field and the sorrounding ground.

c)depressed base plane-horizontal plane depressed into the ground plane,vertical surfaces of the lowered area define a volume of space.

d)overhead plane-horizontal plane located overhead,defines a volume of space between itself and the ground plane.

Vertical elements:

a)vertical linear elements-it defines the prependicular edges of a volume of space.

b)single vertical plane-articulates the space on which it fronts.

c)L-shaped plane-generates a field of space from its corner outward along a diagonal axis.

d)parallel lines-they define a volum of space between them toward both opened ends.

e) U-shaped planes-defines a volume of space that is oriented toward the open end of the configuration.

f)four planes closure-they establish the boundaries of an introverted space and influence the field of space around the enclosure.

Organizing principles of formal and spatial elements are : centralized (a space in which secondary spaces are grouped,linear(repetitive spaces) ,radial( central space from which linear spaces of organization goes into a radial manner,clustered (spaces grouped by proximity or the sharing of a common visual trait) and grid (space organized within a field or structural grid or another 3D framework)
Relation ship of spatial and formal elements is divided into : space within a space -a larger space can contain a smaller space within its volume. Interlocking spaces- overlapping of two spatial fields and the emergence of a zone of shared space. Adjascent spaces -each space is clearly identified. Spaces linked by a common space- two spaces separated by a distance can be linked or related by a third intermediate space.
Openings:
With planes-and opening located within a wall appears like a figure against the background.
At corners- give a diagonal orintation to the space and the planes in which they are located.
Between planes.
Vertical elements:

V. Linear elements-defines the perpendicular edges of a volume of space
Single vertical plane-articulate the space of which it fronts
L-shaped plane-generates a field of spaces from its corner.
Parallel planes-define a volume of space between them toward both opened ends
U-shaped planes-a volume of space which is oriented toward the open ends of configuration
Four planes closure-establish the boundaries of an introverted space.
Solid and cavity has the relationship figure -ground between themselves.
Some architect may start firstly by the design of main forms and then think about space and other details but this is not a good way to choose because the architect should think at the same time for both of them.
Beauvais Cathedral is and example of the design of structural forms for the creation of the fantastically high nave. The stone mass of the cathedral is the reality and then the cavities within the mass. Structural features are treated aesthetically and each of them has almost sculptural form.
The architect can work with the empty space-cavity-between the solids and should consider the forming of the space as the main thing. Architects can be grouped in two categories : Cavity-minded architect, Solid-minded architect depending in the way they design.
The contrast between the solids and cavities creates visual drama in architecture. The employment  of masses and cavities together in effective contrast leads to work that uses grand visual effects.

The contrast between cavities and solids have been used after Renaissance in the period of Mannerism.
Mannerist and Renaissance architect worked with the same forms,they experimented to create combinations that were rich in contrast of form and color.
In modern times Frank Lloyd Wring has created his fantasy over the use of contrasting and effects in falling water house. He used the contrast between the nature and the man made form and the rustic stone and smooth white concrete walls.
Frank uses in his architecture skillful contrast between concave and complex forms, juxtaposition of raw and refined materials, contrasting form and curves.