CBAbench: An AutoCAD-based Dynamic Geometric Constraint System

  • Gong, Xiong (National CAD Support Software Engineering Research Center) ;
  • Wang, Bo-Xing (Huazhong University of Science and Technology) ;
  • Chen, Li-Ping (Huazhong University of Science and Technology)
  • Published : 2006.12.31


In this paper, an integration framework of Geometric Constraint Solving Engine and AutoCAD is presented, and a dynamic geometric constraint system is introduced. According to inherent orientation features of geometric entities and various Object Snap results of AutoCAD, the' proposed system can automatically construct an under-constrained geometric constraint model during interactive drawing. And then the directed constraint graph in a geometric constraint model is realtime modified in order to produce an optimal constraint solving sequence. Due to the open object-oriented characteristics of AutoCAD, a set of user-defined entities including basic geometric elements and graphics constraint relations are defined through derivation. And the custom-made Object Reactor and Command Reactor are also constructed. Several powerful characteristics are achieved based on these user-defined entities and reactors, including synchronously processing geometric constraint information while saving and opening DWG files, visual constraint relations, and full adaptability to Undo/Redo operations. These characteristics of the proposed system can help the designers more easily manage geometric entities and constraint relations between them.


  1. Aldefeld B. (1988), Variation of geometries based on a geometric reasoning method, Computer-Aided Design, 20(3), 117-126
  2. Chen L.P., Tu Z.B., Luo H. and Zhou J. (1996), A new method about constraint management of parametric drawing, Journal of Software, 7(7), 394-399
  3. Chen L.P., Wang B.X., Peng X.B. and Zhou J. (2000), An optimal method of bipartite graph matching for under-constrained geometry solving, Journal of Computers, 23(5), 523-530
  4. Durand C. and Hoffmann C.M. (2000), A systematic framework for solving geometric constraints analytically, Journal of Symbolic Computation, 30(5), 493-529
  5. Gao X.S. and Chou S.C. (1998), Solving geometric constraint systems I: A global propagation approach, Computer-Aided Design, 30(1), 47-54
  6. Gao X.S. and Chou S.C. (1998), Solving geometric constraint systems II: A symbolic approach and decision of re-constructibility, Computer-Aided Design, 30(2), 115-122
  7. He W., Tang M., Dong J.X. and He Z.J. (2003), A constraint solving approach based on graph decomposition, Journal of Image and Graphics, 8(8), 926-931
  8. Hoffmann C.M., Lomonosov A. and Sitharam M. (1997), Finding solvable subsets of constraint graphs, Berlin: Springer, 463-477
  9. Hoffmann C.M. and Vermeer P.J. (1995), Geometric constraint solving in R2 and R3. In: Du D.Z. and Huang F., eds. Computing in Euclidean Geometric, Singapore: World Scientific Publishing, 170-195
  10. Joan-Arinyo R. and Soto A. (1997), A correct rule-based geometric constraint solver, Computers & Graphics, 21(5), 599-609
  11. Joan-Arinyo R. and Soto A. (1999), Combining constructive and equational geometric constraint-solving techniques, ACM Transactions on Graphics, 18(1), 35-55
  12. Kondo K. (1992), Algebraic method for manipulation of dimensional relationships in geometric models, Computer-Aided Design, 24(3), 141-147
  13. Kramer G.A. (1992), Solving geometric constraints systems: a case study in kinematics, Cambridge MA: MIT Press
  14. Lamure H. and Michelucci D. (1996), Solving geometric constraints by homotopy, IEEE Transactions on Visualization Computer Graphics, 2(1), 28-34
  15. Latham R.S. and Middleditch A.E. (1996), Connectivity analysis: a tool for processing geometric constraints, Computer-Aided Design, 28(11), 917-928
  16. Lee J.Y. and Kim K. (1998), Geometric reasoning for knowledge-based design using graph representation, Computer-Aided Design, 28(10), 831-841
  17. Lee K.Y., Kwon H., Lee J.Y. and Kim T.W. (2003), A hybrid approach to geometric constraint solving with graph analysis and reduction, Advances in Engineering Software, 34(2), 103-113
  18. Li Y.T., Liu S.X., Hu S.M. and Sun J.G. (2002), Geometric constraint solving techniques based on symbolic algebra and graphical reduction, Journal of Tsinghua University (Sci. & Tech.), 42(10), 1410-1413
  19. Lin V.C., Gossard D.C. and Light R.A. (1981), Variational geometry in computer-aided design, Computer & Graphics, 15(3), 171-177
  20. ObjectARX 2002 (July 10, 2002),
  21. Owen J. (1991), Algebraic solution for geometric from dimensional constraints, ACM symposium, New York: ACM Press. 397-407
  22. Peng X.B. (2002), Study of principles and methods of 2D/3D united geometric constraint solver, PhD dissertation, Wuhan: Huazhong University of Science and Technology
  23. Wang, B.X., Chen L.P. and Zhou J. (1998), Study and practice of key technologies of geometric constraint driven function in traditional drafting systems, Computer Research & Development, 35(10), 935-940
  24. Zhou J.L., Chen L.P., Wang B.X. and Zhou J. (1999), The total solution for parametric engineering drawing, Computer Engineering and Design, 20(3), 39-41