Understanding the Power of the REGEN Command in AutoCAD
The primary purpose of the REGEN command in AutoCAD is to regenerate the drawing within the current viewport. This means it recalculates and redraws all the elements displayed, ensuring that the visual representation of your drawing accurately reflects the underlying database. When you work with AutoCAD, you’re not just seeing static images; you’re interacting with a complex data structure. Changes made might not be immediately and perfectly displayed on the screen. This is where REGEN comes in, effectively forcing AutoCAD to refresh the display and show a precise representation of your design. This command is crucial for maintaining accuracy and visual fidelity in your CAD drawings.
Why is REGEN Necessary?
AutoCAD uses a dynamic system for rendering drawings. It optimizes performance by only updating the display when absolutely necessary. However, certain operations or accumulation of small errors can lead to discrepancies. For instance:
- Zooming and Panning: While AutoCAD often updates smoothly, it might not perfectly recalculate the pixel positions of every object during rapid zooming or panning.
- Complex Geometry: Drawings with intricate curves, splines, and hatches can sometimes show visual artifacts or jagged edges.
- Large Files: When working with very large and complex drawings, AutoCAD might not refresh the display perfectly in real-time.
- Temporary Graphics: Operations like the VSLIDE command and some temporary constructions can leave remnants on the screen.
REGEN addresses these issues by forcing a complete recalculation and redraw. It essentially cleans up the screen, providing a fresh, accurate rendering of your design.
How to Access the REGEN Command
There are several ways to invoke the REGEN command:
Through the Menu
Navigate to the View menu, and select Regen. This is a straightforward method for users who prefer graphical interfaces.
Through Command Line
Typing REGEN directly into the command line and pressing Enter is another common and quicker approach for experienced AutoCAD users.
REGEN vs. REGENALL
It’s crucial to understand the difference between REGEN and REGENALL:
- REGEN only regenerates the current viewport, the one that is actively being used.
- REGENALL regenerates all viewports in the drawing, regardless of which one is currently active.
Choosing the correct command depends on the situation. If you are only experiencing display issues in one viewport, REGEN is sufficient. If the visual issues are present in multiple viewports, REGENALL is the preferred command.
REGEN and Other Related Commands
Redraw Command
The REDRAW command is often confused with REGEN, but they serve different purposes. REDRAW simply refreshes the display within the current viewport, removing temporary graphics and any visual artifacts, but it does not recalculate the locations of objects. REGEN goes further by recalculating the locations of all objects, thus providing a more complete refresh of the drawing. You can consider REDRAW as a quick screen clean, and REGEN as a more thorough and recalculation.
Regenmode
REGENMODE controls whether AutoCAD automatically regenerates the drawing. When REGENMODE is turned On (value of 1), the system automatically regenerates the drawing when certain actions that can affect drawing display occur. When it’s Off (value of 0), AutoCAD will not automatically regenerate the drawing. Keeping automatic regeneration off can improve performance but may require more frequent manual regeneration.
Frequently Asked Questions (FAQs)
Here are some frequently asked questions to further clarify the purpose and intricacies of the REGEN command:
1. What exactly does regenerating the drawing mean?
Regenerating the drawing means recalculating the display positions and visibility of all objects in the viewport based on the current drawing database, ensuring that what you see on screen accurately represents the underlying data.
2. When should I use the REGEN command?
Use the REGEN command when you observe visual artifacts, such as jagged lines, inaccurate curve displays, or when you suspect that the displayed information is not perfectly aligned with the actual drawing data. It is especially helpful after operations like zooming, panning, or modifying complex geometry.
3. Is REGEN always necessary?
Not always. AutoCAD’s built-in optimization algorithms often handle display refreshes effectively. However, it’s good practice to use REGEN periodically, particularly when working on large or complex drawings or if you encounter display issues.
4. Can REGEN affect the drawing file?
No, REGEN does not alter the actual drawing file (.dwg) data. It simply recalculates and redraws the visual representation of that data within the AutoCAD environment.
5. Does the REGEN command impact performance?
Yes, the REGEN command can impact performance, particularly on large and complex drawings because it requires significant recalculation by the system. It might take some time to complete a regeneration.
6. How can I reduce the frequency of REGEN?
Optimize your drawing by using layers effectively, minimizing the use of overly complex objects, and ensuring that your graphics card and drivers are up-to-date. Turning automatic regeneration off via REGENMODE can also help to reduce regenerations, although you may need to perform manual regenerations more often.
7. What are common causes for frequent regeneration needs?
Frequent regeneration can be caused by working with very complex drawings, using non-standard linetypes or hatches, having out-of-date graphics card drivers, or not using optimized drawing settings.
8. Why does my drawing regenerate when I switch viewports?
When working in multiple viewports, switching to another viewport might trigger a regeneration, especially if the viewports display different parts of the drawing at different scales or perspectives. This ensures each viewport is accurate.
9. How does REGEN affect hatch patterns?
REGEN ensures that hatch patterns are displayed correctly, with accurate spacing and alignment as they are stored in the database. Sometimes a hatch may appear incorrectly until the viewport is regenerated.
10. Can I stop an ongoing REGEN operation?
Yes, you can stop an ongoing regeneration by pressing the Esc key several times. However, the display may not be entirely correct if you interrupt the process.
11. What is the relationship between REGEN and system variables?
System variables such as REGENMODE directly affect how often and when AutoCAD regenerates the drawing. These variables can be modified to customize how the system operates.
12. How does the drawing’s complexity impact REGEN?
The complexity of the drawing – the number of objects, the intricacy of their geometry, the types of objects used (e.g., splines, hatches), and the number of viewports – directly influences the time and resources required for regeneration. More complex drawings take longer to regenerate.
13. How can I monitor system variables in AutoCAD?
You can monitor system variables by using the SYSVARMONITOR command. This opens a window where you can add and track the values of different system variables, including REGENMODE, and reset them to default values if needed.
14. Does REGEN happen automatically?
AutoCAD does not automatically run REGEN command, however, there is an ‘automatic regeneration’ controlled by the REGENMODE system variable. When REGENMODE is set to 1, AutoCAD might regenerate the drawing when zooming or panning, but only in situations that require it.
15. How does the drag mode setting affect regeneration?
The DRAGMODE system variable determines how objects are displayed when they are dragged. While it doesn’t directly cause a regeneration itself, the visual representation while dragging might look different after a REGEN due to the fresh redraw, especially if DRAGMODE is set to ‘auto’.
By understanding the REGEN command and its related functions, you can optimize your AutoCAD workflow and ensure that your drawings are always visually accurate. Proper use of REGEN, alongside other related commands, will lead to more efficient and productive design sessions.