Greg Nelson. Juno, a Constraint-Based Graphics System. Computer Graphics, Proceedings SIGGRAPH'85, San Francisco, CA, July, 1985, pp. 235-243.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....automatically rotates and changes size around the pivot. HyperSnapping does not support moving and rotating at the same time, but similar operation is possible by snapping the anchor point and rotating around it. The history of constraint based drawing editors is very long. SketchPad[10] Juno[9], and many other systems have been developed and various algorithms for solving constraints have been proposed. However, none of them has become popular and widely used, maybe because of the difficulty of programming the constraints. As we mentioned in section 1, the basic idea of Briar[4] is ....

G. Nelson. Juno, a constraint-based graphics system. Computer Graphics, 19(3):235--243, July 1985.

....be placed over the spreadsheet to reveal dependencies between cells. Other examples of relevant user interface techniques include Pad [12, 11] which can be used to organize several spreadsheets at different depths. Spreadsheets are also related to the area of constraint languages and systems [68, 20, 19, 18, 71, 110]. Constraints are relationships that are declared once and then maintained by the system. Constraints are relevant to spreadsheets since values of cells are constrained by equations. Spreadsheets use single direction data propagation, thus can be viewed as one way constraint systems. Although not ....

Greg Nelson. Juno, A constraint-based graphics system. In B. A. Barsky, editor, Computer Graphics (SIGGRAPH '85 Proceedings), volume 19, pages 235--243, July 1985.

....[Press et al. 1994] for solving large sets of linear and non linear constraints among real valued variables. But usually they are not efficient enough for graphical applications and may not converge on a solution for all constraints. For instance, the Newton Raphson iteration (e.g. used in Juno [Nelson, 1985, Heydon and Nelson, 1994] and Converge [Sistare, 1991] changes all constrained variables at each iteration step. The Levenberg Marquardt iteration, a least squares method that is used in Chimera [Kurlander and Feiner, 1993] achieves better numerical efficiency. Frequently, iterative numerical ....

....and introduces a prototype based model; it also proposes to employ (several) special purpose constraint solvers in a modular way. Freeman Benson and Borning, 1992] requires one corresponding constraint solver for each special domain to foster the integration of objects and constraints. [Nelson, 1985] translates geometric constraints into numerical ones to solve them numerically; please further consult also [Heydon and Nelson, 1994] Sriram and Maher, 1986] represents the constraints as objects or as production rules. Duisberg, 1986] refers to the time aspect of the computation; it mentions ....

Greg Nelson. Juno, a constraint-based graphics system. Computer Graphics, 19(3):235--243, July 1985. SIGGRAPH'85, San Francisco, CA, July 22--26, Proceedings, acm press, New York, NY, U.S.A.

....simulation continually updates the position of the nodes in the layout. Although they are not represented graphically, the forces on a node become apparent to users through observation and manipulation. CONCLUSIONS Constraint based techniques have been utilized in numerous drawing editors, e.g. [6, 8, 10, 13, 14], but they have so far enjoyed only limited success in this role. One reason for this apparent failure is the generality and complexity of most constraint based drawing editors: the constraint vocabularies have often been chosen for orthogonality, coverage, and tractability, but may not be ....

Greg Nelson. Juno, a constraint based graphics system. Computer Graphics (Proceedings of SIGGRAPH '85), 19(3):235--243, July 1985.

....user programmable transformations on images. Numerous other application domains have used constraint solvers. Early work includes the drawing tool Sketchpad [41] and the simulation laboratory ThingLab [5] Many other drawing programs have embedded constraint solvers over the years including Juno [31], Juno 2 [21] Unidraw [20] and Penguin [8] Unidraw and Penguin both leverage QOCA, a constraint solver that (like Cassowary) is able to maintain arbitrary linear arithmetic constraints [24] Scwm includes more than just constraints in its support for intelligent window layout; another paper ....

Greg Nelson. Juno, a constraint-based graphics system. In Proceedings of SIGGRAPH 1985, San Francisco, July 1985.

....interpretation, on the basis that most changes to the sketch tend to make only minor changes to the 3D interpretation. Second, the user must be able to make the sketch more accurate as the design process advances. An obvious way to do this is to allow the user to place constraints on objects. [Nelson 1985] describes a system for placing and solving systems of non linear constraints in two dimensions. One characteristic of this system is that it uses the current position of the points when searching for a solution to a new system of constraints, on the assumption that the positions will not change ....

Nelson, G. 1985. Juno, a Constraint- Based Graphics System. Proceedings, SIGGRAPH '85. Edited by B. A. Barsky. 235-243.

....of the Sketchpad system by Sutherland as early as 1963 [16] the notion of constraints has played an important role in computer graphics and computer aided design. Applications include the design of mechanisms [14] user interfaces [2] and [3] interactive dynamics [11, 17, 18] 2 D graphics design [7] and [10] and the combination of 3 D geometric design and mechanism simulation in the LEGO system [6] In all these applications, geometric constraints take the form of coupled nonlinear equations and inequalities. Unfortunately, quoting the authors of Numerical Recipes in C ( 13] page 379) ....

....method does not necessarily have to be faster than a linear method. 364 etc. In the system, constraints were dealt with in a locally linearized fashion and the coupling between the constraints was taken care of by means of solving a set of coupled linear equations. Also in 1985, Nelson [7] published a paper on the Juno system, based on a declarative language for specifying constraints for 2 D drawings. The constraints in Juno were solved by means of NewtonRaphson based global error minimization. In 1986, Borning and Duisburg [2, 3] reported on the application of constraint solving ....

G. Nelson (1985). Juno, a constraint based graphics system. Computer Graphics (Proc. SIGGRAPH 85) 19, pp. 235--243.

....dependency relations between things . The nature of these things very much depends on the environment in which the constraints are used. Typical areas in which constraints are used are user interface control [5, 23] with check buttons, radio buttons, bars, boxes, etc. geometric layout [24, 25, 26] (with circles, rectangles, lines, points, etc. animation [5] with timetables, sprites, still images, palettes, etc. and media synchronization [3, 12] with timetables, media objects, error functions, etc. However, the precise nature of these things is not relevant for this discussion; in ....

Nelson G. (1985). Juno, a Constraint Based Graphics System, in SIGGRAPH, 19, pp. 235--243, ACM.

....and exploring toleranced behavior[24] Since the earliest interactive graphical systems[29] constraints have been used to aid in the manipulation of geometry. From the early systems, numerical techniques to solve these constraints have been employed. Modern constraint based systems, such as [4, 9, 19, 26], employ iterative numerical techniques. These non linear system solving techniques, like the techniques for physical simulation and constrained optimization, all rely on repeatedly setting up and solving systems of linear equations based on the derivatives of model functions. All of these ....

Greg Nelson. Juno, a constraint based graphics system. Computer Graphics, 19(3):235--243, 1985. Proceedings SIGGRAPH '85.

....which may be application specific or may depend on the editing mode. Third, while some associations can be described as constraints, our system does not require the rigid formality and associated solution machinery found in mechanism editors based on underlying geometric constraint systems [36, 8, 35, 28, 24]. A novel feature that emerges naturally from our approach is an automated implicit grouping mechanism; it uses the relationships established between objects as they reposition themselves with respect to their environment. 3.2.1 Overview The object associations mechanism is based on a two phase ....

Nelson, G. Juno, a Constraint-Based Graphics System. Proc. of SIGGRAPH '85 (San Fransisco, CA, Jul. 22-26, 1985). In Computer Graphics 19, 3 (Jul. 1985), pp. 235-243.

....editors are perhaps one of the oldest ideas in computer graphics. Sutherland s Sketchpad (1963) introduced the notion of interactive graphics and incorporated the ideas of direct manipulation, and constraint satisfaction. Subsequent research led to systems such as ThingLab (Borning, 1979) and Juno (Nelson, 1985); these early systems provided a limited set of graphic primitives and constraints. Juno2 (Heydon and Nelson, 1994) expanded upon this work. This system is a double view drawing editor, which presents the user with a WYSIWYG graphical representation, along with a text based version of the program ....

Nelson, Greg. 1985. Juno, a constraint based graphics system. Computer Graphics (Proceedings of SIGGRAPH '85), 19(3):235--243, July.

....the appropriate constraints for changed part of the object. This plan was then repeatedly executed while the manipulation continued. Works following the THINGLAB tradition included the Filters Project [81] and Animus [80] Another graphical system, this one focusing on geometrical layout, was JUNO [196]. The constraints were constructed, as in THINGLAB, by text or graphical primitives, and the geometric object could be manipulated. A difference from the abovementioned works is that constraint solving was performed numerically using a Newton Raphson solver. Another collection of early works ....

G. Nelson, JUNO, A Constraint Based Graphics System, Computer Graphics 19(3), 235--243, 1985.

....current selection. In the latter case, the new view is often displayed in a second window. Magic lens filters can be used to encapsulate these modes in movable regions, making it easier to coordinate the different views. For example, a lens could be used in two view editing systems such as Juno [13] or Tweedle [1] or two view user interface editors [2] to visualize one representation in the context of the other. Magic lens filters can also be used as a debugging tool for programs that display data by displaying a textual description of the data. The text may be either the original ....

Greg Nelson. Juno, a constraint-based graphics system. Proceedings of Siggraph '85 Computer Graphics, Vol. 19, No. 3, ACM, 1985, pp. 235-243.

....(See also [Le87] where similar principles are applied in a different style. At present, our prototype system gives very limited support for constraints, but this does not reflect any difficulty of implementation other than that inherent in constraint manipulation as described in [Bo86] and [Ne85]. It should be possible to implement methods for constraint handling quite as sophisticated as these by plagiarising [Bo86] and programming in EDEN rather than SmallTalk, for instance Though there might be some virtue perhaps eg some simplification in translating techniques from an ....

G Nelson, Juno, a constraint-based graphics system, SIGGRAPH '85, p235-243

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Greg Nelson. Juno, a Constraint-Based Graphics System. Computer Graphics, Proceedings SIGGRAPH'85, San Francisco, CA, July, 1985, pp. 235-243.

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Nelson. G. Juno, a constraint-based graphics system. Computer Graphics, 19(3):235--243, Proc. SIGGRAPH'85.

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G. Nelson. Juno, a constraint based graphics system. Computer Graphics (Proc. of SIGGRAPH '85), 19(3):235--243, July 1985.

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Nelson, G. 1985. Juno, a constraint based graphics system. Computer Graphics (Proc. of SIGGRAPH '85) 19(3):235--243.

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G Nelson. Juno, a constraint-based graphics system. In SIGGRAPH '85 Conference Proceedings, pages 235--243, July 1985.

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Greg Nelson. Juno, a constraint-based graphics system. In SIGGRAPH, pages 235--243, July 1985.

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Nelson, G. Juno, a Constraint-Based Graphics System. In Proceedings of the ACM/SIGGRAPH Conference, 1985.

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Nelson, G. (1985). Juno, a constraint based graphics system. Computer Graphics, 19(3) (Proc. of SIGGRAPH '85), pp. 235-243.

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Greg Nelson. Juno, a constraint-based graphics system. In Proceedings of the 12th annual conference on Computer graphics and interactive techniques, pages 235--243. ACM Press, 1985.

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Greg Nelson. Juno, a constraint-based graphics system. In Siggraph '85, pages 235--243. Xerox Palo Alto Research Center, 1985.

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G. Nelson. Juno, a constraint-based graphics system. In ACM, editor, GIG-GRAPH'85 Conference Proceedings, pages 235--243, San Francisco, July 1985.

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