• 2D speed

This article describes the how to tackle 2D speed issues in ArchiCAD - what functions and components affect 2D speed and how to fine-tune your system and your ArchiCAD for optimal performance.

Phenomena

"slow 2D" usually means either of these two phenomena:

• Rebuild is slow. Rebuild occurs every time after you pan or zoom, or when you use the rebuild command from the View/Refresh menu.

• Feedback is slow. By feedback we mean all the temporary visual items that appear during the process of element editing, e.g. the ghost elements that follow the cursor when you drag something, or the rubberband that follows your cursor while drawing a wall.

It is important to differentiate between rebuild and feedback related performance problems, since they usually have a different cause.

typical feedback problem: rubber band not following the cursor

Functionalities and components affecting 2D performance

General ArchiCAD elements

The more elements you have, the longer it takes to draw them on screen. ArchiCAD optimizes what elements need to be refreshed after a change in the drawing, so editing elements is not typically slower in a large file than in a small file. Also, if you are zoomed in into a large floor plan, ArchiCAD will ignore rebuilding the elements that are outside the display area, so panning and zooming will be instant.However, if you zoom out, and more elements are displayed, then the rebuild time after panning and zooming will increase, since more and more elements are on your screen. This behavior is normal.

During panning, while you keep the mouse button pressed and drag the screen, the ArchiCAD elements follow your cursor. The level of this feedback can be controlled by a Work Environment setting called Model Display in 2D Navigation. This setting is under Options/Work Environment/More Options and its possible values are: Structural Contours Only, Simplified Model and Full Model. In Full Model mode you see every ArchiCAD element during panning and Zooming, the other options filter the elements being displayed during navigation, thus giving a better refresh rate.

Vectorial fills

Vectorial fills are scale-dependent, which means that they need to be recalculated if the zoom level changes. Depending on the zoom level and the pattern and the size of the fill, this could mean hundreds of thousands of lines that have to be calculated and drawn on screen. For optimizing redraw speed, if the density of the pattern reaches a certain level (when you can't tell apart the different lines in the fill), ArchiCAD substitutes the pattern with a solid fill. However, to further increase 2D speed during drafting, ArchiCAD can substitute vectorial fills with scale-independent bitmap fills. Go to View menu/On-Screen View options and deselect theVectorial Hatching option. The appearance of the fills will change on screen, but this option will not affect the output - the fills will print with the correct scale.

GDL elements

Smart objects intelligently react to their environment. E.g. a window cuts a correct size hole in the wall, and a room stamp displays the exact area of the room. To keep these element up-to date, their script has to be run again if something that may affect their behavior is changed. This background calculation adds to rebuild times. Needless to say, not all GDL elements are recalculated after each change to the drawing, but the first opening of a view that contains many GDL objects could be relatively "slow". To optimize speed, you can set the object's 2D detail level to low while drafting.

Virtual Trace

Also read: Virtual Trace

It might, or might not be obvious that using a Trace Reference adds some extra time to the rebuild time of the active window, as there are more elements displayed on the screen. During rebuild (after panning/zooming), the content of the Trace Reference is also refreshed. If the Trace Reference is a section or an elevation, then the 3D model also needs to be partially rebuilt so that the changes propagate to the appropriate views. This step (partial rebuild of the model) can be considerably slower than rebuilding a view with only 2D content. As a result, the overall rebuild time of the active window if a Trace Reference is used can be significantly slower than without the Trace Reference.

You can disable automatic refreshing of the Trace Reference either with:

• using manual rebuild Sections and Elevations

• setting option Project Preferences/Miscellaneous "Update Autorebuild Model viewpoints continuously" off*.

*Note that this setting has an effect on the behavior of all of the sections/elevations in the project. When working in these views, you will need to manually rebuild them after you have edited elements, otherwise elements will temporarily not show properly after editing. (e.g. you move a wall, and the intersection with other walls will not clean up until you hit rebuild)

The use of View map items as Trace Reference

If you wish to use e.g. an elevation as Trace Reference under your floor plan, you can do it in two ways:

• Select the elevation in the navigator’s Project Map, and select “show as Trace Reference”

• Select the elevation in the navigator’s View Map, and select “show as Trace Reference”

In the first case, the Trace Reference will use the same layer settings and model view options as the active view. In the second case, the Trace Reference and the floor plan will use different layer settings and model view options. This latter scenario will result in a slower 2D rebuild, because the refreshing of the Trace Reference involves changing layer and model view states. So, if possible, use Project Map items instead of View Map items as Trace Reference

Hardware optimization

Generally speaking, the CPU has the most effect on how "fast" your 2D display is. However, for some drawing functions, ArchiCAD uses hardware acceleration provided by the graphic card.

ArchiCAD 11 uses new 2D display technology to display temporary visual feedback items, such as rubber bands, guidelines, element highlights, etc. Up to ArchiCAD 10 these items were displayed by just simply repainting the necessary pixels on the display. From ArchiCAD 11 the overlay technology is used, which means that ArchiCAD uses multiple drawing “layers” to display different overlaying items. This enables smoother transitions and nice semi-transparent effects at no cost of performance, since these effects make use of the hardware acceleration provided by video cards. On the PC platform ArchiCAD uses DirectX technology, on the Mac platform ArchiCAD uses the Quartz drawing engine, which manages the OpenGL hardware acceleration provided by video cards.

On PC, when ArchiCAD starts, it automatically checks if DirectX version 9.0c is supported by the system, and if not, ArchiCAD will use software emulation to emulate the same effects at the cost of CPU time. On Mac, hardware acceleration is handled by the system (Quartz engine) so there is no direct hardware acceleration control in ArchiCAD. If there is a problem with hardware acceleration, the phenomenon is that feedback during element editing is not instant. The most visible phenomenon occurs while dragging a Trace Reference, as this is the situation where the temporary visual feedback is the most complex. Hardware acceleration does NOT affect rebuild times.

PC users: to optimize DirectX settings, and to learn how to disable hardware acceleration, read article DirectX

Reporting 2D speed related bugs

If you believe that you are experiencing abnormal 2D performance, please contact your local ArchiCAD distributor with the following details of the problem:

• a step-by-step description of a concrete example where ArchiCAD is slow. E.g.: "I open the view Elevation/West Elevation with no Trace Reference on. I select and drag a couple of lines. The feedback during dragging the elements is instant, but after I click to place the elements, the hourglass cursor appears for 6-7 seconds"

• Start the GSReport application in your ArchiCAD folder and save a .rep file. This captures your system's components and settings

• Send an example ArchiCAD project file in archive (.PLA) format. This is necessary even if the problem is not file-specific, as the file includes your common project preference settings.

• If possible, send a screen capture movie that captures the problem

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