IntroductionToday architecture industry faces many challenges that revolve around occupant comfort, cost-effectiveness, and energy saving. Computational optimization is essential since it solve contemporary challenges in architecture. Architects utilize biologically inspired techniques, Artificial Neural Networks, swarm intelligence, and evolutionary algorithms to discover high-performing design solutions. The influence of optimization techniques is more to the engineering design than in architecture professions despite its core role in architectural research. The architects rarely use optimization method since the architectural design is associated with time complexity and intensity. The field of mathematical optimization is more vigorous as compared to the general optimization method according to ADO evaluation. Nevertheless, contemporary researchers in architecture use problems of quantitative benchmark to test optimization techniques. Complex design problems require specific optimization method to be solved. However, application of optimal design solutions among practitioners is hard due to variously available barriers. The use of computer science in architecture especially in design optimization has elevated most optimal design problems through the development of robust optimization and user-friendly tools and software. Energy and cost-effective, comfortable as well as safe buildings are the main focus of design optimization in real life. The paper aims to explore the use of the digitalized methodologies in architecture design optimization. The essay centers on major types of digital design optimization, digital technology in designing, and computerized approaches used to generate designs.Types of digital design optimization Genetic Algorithm method: It is a powerful method for building and architecture design when associated parameters are incorporated. The designs of algorithms-based parametric are efficient when utilized to construct geometry models since the adjustment of the geometry parameter is easy hence it is possible to have a tailor-made design. Genetic reproduction and genetic evolution principles form the basis of a search method such as the genetic algorithm to optimize geometry designs. Additionally, it is possible to optimize geometric designs parameter through the uses of various tools such as an integrated design. Binary genotype or string encoded from design variables is a representation of design due to geometry modelling and evolutionary search algorithm tool like a Generative Component. The use of natural selection, mutation, and the crossover is common in design alternatives. The tool enables design optimization to be executed using any geometry parameters and parametric graph variables combination. Geometry attribute that is user-defined is an example of fitness score used to evaluate a design solution. During the evaluation, every new design has one fitness score. Subsequent design solution occurs if more solutions are selected (Gololov, I. and Yezioro, A, 2007). Hence, natural selection emulation leads to optimized generation. Ultimately, practical design of sports stadium and the solid-simple case has been possible via the use of an integrated tool in genetic algorithm method.Non-linear and linear design methods: Examination of two or more design process is critical during architectural design. Initially before the intervention of computer science in architecture, great human labor, as well as time, was mandatory to successful evaluate each design alternatives. There are two major changes in designing as a result of the introduction of computer-oriented design. The first change is the capability of architects to deform and handle forms of architectures. The new change reduced the time to create design alternatives. Limited time is required to replicate and produce physical model30, 3-D virtual, and alternative from a 2-D drawing. The second method is where the alternatives designs are generated through the use of computer processing power (Januszkiewicz, K., & Banachowicz, M, 2013). The degree and type of deformation in the generated alternatives are controlled by the designer. Consequently, development of various designs is possible and specific alternative can be produced at undesignated stages.Digital tools used in 3-D design optimizationModeling and Drafting software: There are two types of soft wares which cover most of the tools architects use are featured in this category. The first software is the drafting software. It mainly used in the development of 2-D documentation and designs since its 3-D modelling capability is limited. The 2-D designs still serve as the major method of communication that the architects and structural engineers use. The 3-D modules contained in the software majorly offer orthogonal modelling options that are based on polygon meshes and solid modelling hence only present limited options for free-form design. Vectorworks, Arc+, Datacad, Microstation and Autocad are the leading software programs. Also, several other applications are available but have limited presence in the market. The other type of software is modelling software. It is designed for architectural use such as models production, presentation, modelling, and design. In some instances, it is an animated software version that is limited. 3D VIZ which is a limited version of 3ds Max is among this category’s commercial software (Aly, M. and Nassar, K, 2013).Parametric software programs for architects: The introduction of the first parametric applications happened in the 1980s. The effort by this time to develop an application which uses computer-based generation of the plan of a project to solve “problem of space allocation” had been reduced. The development of programs that are human-machine interactive in which a designer uses computer program referred to as design companion to develop a design instead of using drawing board was the main focus of the initial parametric applications. The approach was used to develop applications that were mostly 2-D whose number of entities that could be handled were limited. Therefore, it was necessary to employ the combination of methods hence the suggestion to use the combination of an evaluation method and the generative method made in 1987. The development of the second generation of parametric software for architectural use was in the 1990s. The software provides the solution for the need for both 2-D documentation and 3-D modelling. The sections and plans are derived from the similar 3-D model in the software. Tool for documentation as text or dimensioning is inclusive in the software. The full integration of technique of free-form design is not yet in this software hence presenting a limitation regarding the formal expression of the design. Some of the leading software here are Revit, Architectural Desktop and Archicad. A parametric software called Generative Components with the definition of complex constraints capability is currently under development in Bentley.Modelling software originally designed for other professions: Architects use a majority of modelling software that was originally developed for use in other fields such as industrial/mechanical and animation design. The software is mainly used in the average architectural companies for representation and modelling, either as for its final product representation or as a component of the design process. Free-form elements manufacturing and design is another important use. Complex forms manipulation and creation can be done by the use of software programs created for mechanical and industrial design. Also, the programs can export directly to RP and CNC machines and contain necessary modules for real material performance calculation. The leading programs here are Form Z, CATIA and SoftImage among others (Arvin, S. A., & House, D. H, 2012).Computer-based generative design methods The ability of computer-aided designs to generate building from data was expected to replace conventional designs in early days. Therefore, some of the developed-generative systems aimed to utilize processing powers of a computer in spatial design completion to overcome limitations that occur when designers process the information of models and designs. Moreover, computer-aided designs assist in the modeling of building plan layout through the use of less comprehensive approaches.Cellular automata: Cellular Automata (CA) is one of the earliest tools used in computer form generation. It mainly began as a software that simulates 2-D growth and is based on the 1940s theories of Von Neumann about self-replicating forms. The adaption of CA in architecture is in various ways such as the use of CA to predict or simulate the cities’ growth and in development of complex formal expressions. CA is capable of creating conceptual forms that are highly complex hence can be used for inspiration of finding process of an architectural form. For instance, the CA-based algorithm can be used in the generation of building façade pattern..Automated floor plan generation/Space allocation: Various principles can be used in automated space allocation and generation of the floor plan. Using the programmatic information in generating building plan was the main focus of the earlier approaches. Majority of the approaches centered on 2-dimension plans generation but some used excluded planes (2.5-dimension). The above mentioned approached demonstrates the generation of floor plan ability through the production of prototype tools, but neither have much commercial application in building plans generation nor substantial influence on architectural practices due to various reasons (Januszkiewicz, K., & Banachowicz, M, 2013). First is the complexity of the problem. Space allocation has little programmatic demands that architects take into consideration during the generation of a plan. The second reason is the singularity of each building. Each project requires new definitions of rules since the program for every building is unique. Finally, it requires three dimension which is complicated and difficult to solve.ConclusionThe introduction of the computer in architectures has a wider scope of influence. One of discipline that has a wider application is the design optimization through the use of digital methodologies. The use of digital methodologies optimization and simulation in the design process has enhanced the position of architects in the building discipline. The simulation process in the design process enables the architects to solve problems during the process. The tools or technologies do not automate the process completely but are useful in design evaluation and generation. The designers use the approaches in subjective and quantitative judgments as well as in maintaining control where appropriate. The continuous progress in the use of digital methodologies in the design optimization is made possible by the production of appropriate software for the various approaches.ReferencesAly, M. and Nassar, K. (2013). Integrating performance and parametric design tools for urban daylight enhancement. Proceedings of BS2013: 13th Conference of International Building, (pp. 3028–3034). Le Bourget Du Lac, France.Arvin, S. A., & House, D. H. (2012). Modeling architectural design objectives in physically based space planning. Automation in Construction, 11(2), 214-225.Gololov, I. and Yezioro, A. (2007). A computer system for multi-criteria comparative. A computer system for multi-criteria comparative evaluation of building envelopes, (p. 1903). Beijing, China.Januszkiewicz, K., & Banachowicz, M. (2013). Nonlinear Shaping Architecture Designed with Using Evolutionary Structural Optimization Tools. In IOP Conference Series: Materials Science and Engineering. 245, pp. 1-9. IOP Publishing. doi:10.1088/1757-899X/245/8/082042.