عنوان مقاله
روش انتخابی Undo/Redo در محیط مدلسازی گروهی 3 بعدی
فهرست مطالب
مقدمه
کارهای وابسته
حفظ همسانی در سیستم مدلسازی گروهی سه بعدی
الگوریتم Undo/Redo
نتیجه گیری
بخشی از مقاله
اجرای Undo برروی سایت محلی
زمانی که سایت محلی یک عملیات O را برای undo (بی اثرسازی) انتخاب می کند، بلافاصله برروی سایت محلی اجرا می شود. در طول این دوره، او بایستی از یکی از دو ویو یا نمای تاریخچه استفاده کرده و گزینه مناسب را انتخاب کند.
در صورت ارائه یک دستور undo برروی سایت محلی، ابتدا عملیات اصلی چک می شود تا مشخص شود آیا قبلاًundo شده است یا خیر. اگر چنین باشد، این درخواستundo متوقف می شود. در غیر این صورت، حالت مدل را به حالتی برمی گردانیم که عملیات قبل از O اجرا شده، مجموعه وابستگی اش را دریافت ، USV را گسترش و عملیات های موثر را درست بعد ازO مجدداً اجرا می کند.
کلمات کلیدی:
Proceedings of the 2012 IEEE 16th International Conference on Computer Supported Cooperative Work in Design A Selective Undo/Redo Method in 3D Collaborative Modeling Environment Yuan Cheng School of Computer Science Wuhan University Wuhan 430072 P.R.China graphics@whu.edu.cn Xiantao Cai School of Computer Science Wuhan University graphics@whu.edu.cn Abstract-In 3D collaborative modeling systems, users need a convenient mechanism to repeatedly modify the models they are operating on. In this paper, we contribute a selective undo/redo solution for users to select arbitrary operation to undo. With the consistency maintainence mechanism we proposed, operations need to be re-arranged on each site for after their arriving. Both history butTer and model state stream are adopted to present the arriving sequence of operations and their actual execution sequence. In case of concurrent undo/redo, undo state vector is proposed to make sure that an operation can only be undone once and redone by the designer who undoes it. Based on all the precautions we have made, an undo/redo algorithm is proposed. The algorithm has been verified in the prototype we implemented. Keywords-3D collaborative modeling; Model State Stream; Concurrent undo/redo; I. INTRODUCTION Human plays an instructive role in interactive systems. From the perspective of collaborative CAD systems, the ultimate designing result is the embodiment of mutual intention of clients and group designers. Objectively speaking, it is inevitable that designers may make mistakes during the designing process. Simple slips and lapses at this level account for roughly 60% of human errors. The highest cognitive level is knowledge-based, where tasks are approached by reasoning from fIrst principles, without the aid of previously-formed rules or skills; mistakes at this level account for the 10% of human errors[l]. All in all, during the process of searching for optimal solution, designers need to undo some of the executed operations to roll back the document state and then execute a series of new operations to try for different solutions. Being a widely used error recovery mechanism, UndolRedo can fully meet the requirements of error recovery and optimal solution exploration in interactive systems. It is more indispensable in collaborative editing systems. In such systems, data are replicated on each site so designers from different site 978-1-4673-1212-7112/$31.00 ©2012 IEEE
