Composition in Perspectives, Elodie Fourquet

Composition in Perspectives,

Elodie Fourquet.
Proceedings of Eurographics Workshop on Computational Aesthetics in Graphics, Visualization and Imaging,
(Lisbon, Portugal, June 18 - 20, 2008). 9 - 16. EG digital library. [pdf preprint]
Paper preprint on author's site since July 2009. (Permitted by copyright).

Abstract
Composition is a key element of image aesthetics. However composition is hard to control when working in three dimensions to create a two dimensional image. A framework that derives perspective from a planar pattern is proposed and implemented. The third dimension is elevated from a tiled floor into a planar square pattern. Key points on the image allow users to modify the spatial geometry of the scene. Thus, this paper presents a new view on perspective, where there is no concrete third dimension, but where the third dimension is inferred from lines and points in the image plane from which apparent depth relationships of the scene are constructed.

In describing the framework, the computational relation between elements such as vanishing point, distance points and floor lines inside the geometric grid, are exposed to demonstrate the characteristics of building a realistic, yet, composed, image based on the practices of Renaissance painters.

Slides

Below is the summary in images of the publication, with the definitions used. The initial framework is an implemention of an environment, where Talbot's construction methods for Renaissance perspective, can be reproduced [1].

Definitions

Horizon line, H : The horizontal line containing the vanishing point.
Pictures are normally hung with this line at the height of the viewer's eyes.
Baseline, B : The horizontal line defining the bottom of the picture.
Floor orthogonals, f.o : Lines along tile edges perpendicular to the picture plane in 3D.
Intersections of floor orthogonals with the baseline define horizontal tile divisions.
Vanishing point, VP : The point on the horizon line where floor orthogonals meet.
Distance point, DP : A point on the horizon line where diagonal lines in the tiled floor meet. The position of the distance point with respect to the vanishing point and the edge of the picture defines the distance from the eye to the picture. Of the two distance points only one is needed to define the construction.
Main orthogonals, m.o : The two floor orthogonals from the vanishing point to the bottom corners of the picture.
Floor parallels, f.p : Lines along tile edges parallel to the picture plane in 3D.
Horizontal lines at the edges of tiles define the foreshortening at different depths.
Distance point diagonal lines or floor transversals, f.t : Lines from a distance point to intersections of the baseline with the floor orthogonals. Intersections of floor transversals with the main orthogonals locate the floor parallels on the picture plane.

Image Plane Grid

Two configurations of grid of squares providing the image plane geometry in the framework.
The grids show the recursed inscribed pattern.

Tiled Floor in Perspective

1x1 grid, DP on frame

2x1 grid, DP outside frame

2x1 grid, DP close to VP

Pictorial Volumes

Setting intermediate back wall

Room with volume extended in depth

Same scene with DP closest to VP

Intermediate back wall off-centered

Cube looking volume

DP in between side images

Tunnel looking volume

Same as above with wider tile on baseline

Blocks

Multiple blocks. The right image is produced from the left image, by changing the picture edge and with the DP outside the image frame.

Results

Composition based on The Holy Trinity, c.1428, of Masaccio.

Composition based on Madonna and child, c. 1437, of Jan van Eyck.
Two different view configurations.

Hybrid composition inspired from perspective construction and composition in the Flagellation of Christ, after 1444, of Piero della Francesca.

Demo

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References
1. Richard Talbot, Speculations on the Origins of Linear Perspective , Nexus Network Journal, vol. 5 no. 1 (Spring 2003).


1x1 grid, DP on frame	2x1 grid, DP outside frame	2x1 grid, DP close to VP


Setting intermediate back wall	Room with volume extended in depth	Same scene with DP closest to VP	Intermediate back wall off-centered

Cube looking volume	DP in between side images	Tunnel looking volume	Same as above with wider tile on baseline


Composition based on The Holy Trinity, c.1428, of Masaccio.


Composition based on Madonna and child, c. 1437, of Jan van Eyck. Two different view configurations.	Hybrid composition inspired from perspective construction and composition in the Flagellation of Christ, after 1444, of Piero della Francesca.