Between the Lines

DWF vs PDF

Link to results of some testing for the formats with AutoCAD design data.Click Here

Cheers,
-Shaan

"Intel eyes 64-bit chips for desktops" What Is that - Intel Changes to the AMD 64 bit architecture???

There is a very interesting article and many more on the web in the last few days solidifying many of the things I have been hearing recently. The AMD 64-bit architecture with a 64-bit chip supporting native 32-bit applications seems to have turned Intel another direction to do the same instead of the current Itanium which only emulates a 32-bit environment thus making the 32-bit applications run slower. Intel will be showing its codename Yamhill chips in about a month. The biggest question I have is will it be compatible with the AMD 64-bit architecture or will we be unfortunately have two 64-bit Windows operating systems required and two versions of each application for the different architectures, I sure hope not.

It will be interesting to see what happens but the market chatter and machines selling by AMD definitely show that architecture is the right method for a 32-bit to 64-bit transition in the market. Evolution, not Revolution.

http://news.com.com/2100-1006_3-5149859.html

Cheers,
-Shaan

New Autodesk Revit 6 Release Review by AECbytes

There is a good review of the newly released Autodesk Revit 6.
In the article there is a big project screen shot image of a project in Australia in AECbytes.

http://www.aecbytes.com/review/Revit_6.htm

Cheers,
-Shaan

Helpful AutoCAD Solutions for Corrupted Drawings

Corrupted drawings unfortunately occur for a wide variety of reasons such as a bad network or hardware, operating system issues, media degradation like files on old disks, unexpected data or defect, a 3rd party application, or a non Autodesk product saving a DWG file. Here are a couple solutions to assist in recovering the files.

Recover damaged drawing files
http://support.autodesk.com/getDoc.asp?id=TS67106

Difference between AUDIT and RECOVER commands
http://support.autodesk.com/getDoc.asp?id=TS54343

Recovering a damaged drawing if the RECOVER command is not successful
http://support.autodesk.com/getDoc.asp?id=TS19369

Using DesignCenter to recover a drawing and retain layouts
http://support.autodesk.com/getDoc.asp?id=TS43354

Cheers,
-Shaan

Print on Demand User Guides from Autodesk Now Available

For those that want the printed user guides, you can now purchase all of your printed user guide product manuals at the Autodesk eStore. I agree that sometimes I need a paper-based manual but do use the online Help the majority of the time. No more killing trees for those that were not going to read the paper versions is what started as a trend with many software companies a few years back. In fact I heard personally the complaints from customers with hundreds of seats of products, and they were shocked to get hundreds of printed manuals back a few years ago. Of course all of the product documentation is in the product's help system, but we now give you multiple options to suit your needs. Most products at least have a printed user guide and install guide in the box, but if you want more just go order them from http://estore.autodesk.com/.

Currently listed User Guides on the eStore:

AutoCAD 2004 User Guide

AutoCAD 2004 Customization Guide

AutoCAD 2004 Command Ref Vol I/II Doc Pack

AutoCAD 2004 Network Admin Guide

AutoCAD 2004 ActiveX/VBA Dev Guide

AutoCAD 2004 Visual LISP Tutorial

AutoCAD 2004 Visual LISP Dev Guide

AutoCAD 2002 User Guide

Architectural Desktop 2004 New Features

Civil Design R2i User Guide

Land Development Desktop R2i User Guide

Survey R2i User Guide

Direct link to the eStore page with the User Guides: Click Here

Cheers,
-Shaan

Now back to your regularly scheduled program. ;-)

Well, I Have My Amazon Jungle Excursion All Planned

I have decided after my planned business trip to São Paulo Brazil at the beginning of March that I will be taking a week off and going up the Amazon starting at Manaus Brazil. Some people think I am nuts but this is one of those things I have always wanted to do. I have to give great credit to my wife for allowing me to go and being so supportive although she did mention something about life insurance. This is something I have always wanted to do since a child reading National Geographic Magazine and also being addicted to the Discovery Channel. It is a fifteen and a half hour flight from San Francisco to São Paulo then another 4 hour flight up to Manaus which is only accessible by plane or boat. Imagine all of those frequent flier miles… and the sore legs and back from sitting so long on planes.

I will be on the Rio Tarumã tributary of the Rio Negro right in the middle of the Amazon away from civilization, phones and computers. I will be taking photos constantly and posting many of them. I hear currently the temperature is only about 115 degrees F and muggy. It is going to be one of the great adventures of my entire life. I will be fishing for Piranha stalking snakes, gators, and monkeys as well as seeing some of the natives.

I will provide more details and the contact info of the very helpful and friendly tour operator as soon as I get all of the details and plans secured.

Cheers,
-Shaan

São Paulo Brazil, world's second-biggest city, celebrates its 450th birthday!

Yes, the second largest city in the world celebrates it's 450th birthday.

Speaking of São Paulo Brazil, any of my blog visitors from there? I will be there in about a month (March 2004) for business. While there, I hopefully will take a couple days for sightseeing and away from phones and computers. Looking at possibly three Brazilian locations so far besides São Paulo.

The locations of interest are:

In the Amazon Jungle doing some fishing about 65-80 km from Manaus, Brazil

Aimlessly wandering the beaches in Rio and sampling the local caipirinhas by night and local coffees in the morning.

Swimming with the local dolphins in Recife and working on a tan.

Any Brazilian CAD geeks want to get together for some chat over coffee while I am there? Send me an email at shaan@autodesk.com with the subject line of "Brazil CAD Chat".

Cheers,
Shaan

Autodesk Design Awards 2003

Professionals and students submitted their designs for the Autodesk Design Awards in the Fall of 2003. Winners were announced in December at Autodesk University in Las Vegas, Nevada.

Have a look at the winners as there are some really impressive designs:
Click Here

Cheers,
-Shaan

The Great 64-bit CAD Precision Misconception

I just read the January 2004 Cadalyst magazine and spotted an article error or confusion point. The error or confusion is an easy one to fall into in fact I too was thinking the same misconception awhile back until I researched the 64-bit processors from AMD and Intel in greater depth for my floating point (accuracy/prescision) posts in this blog titled 64 bit Computers & AutoCAD, More on 64-bit Processors and AutoCAD and also, More from the AutoCAD Accuracy Universe and the Floating Point.

You cannot connect the 64-bit processor to greater CAD accuracy or precision, but that is just what the article "HP Pioneers 64-bit Computing" did in it's table "How Does 64-bit Computing Compare to 32-bit."

The article is correct in the accuracy of 64-bit floating-point precision, but did not mention that AutoCAD has had 64-bit floating-point precision since the early 1980s. You do not need a 64-bit chip to get 64-bit accuracy, as it is already on their 32-bit processor. In fact you can get a maximum of 80-bit on the 32-bit processor. The 64-bit processors do not provide any benefit to precision. The main benefit of 64-bit is the addressable memory, which does not equate to precision. You do not really gain any speed at this point either.

I do not think a true 64-bit native application for CAD is any benefit to the majority of CAD users unless they are dealing with models that require more addressable memory space and have extra cash burning a hole in your pocket. Currently with the AMD 64-bit chips, you can install your current 32-bit applications and in the case of AutoCAD 2004 it runs up to 40% faster with no porting. The AMD 64-bit runs 32-bit applications in a native mode and with the benefit of a faster bus speed of almost double the Intel and faster floating-point calculations, which CAD requires for accuracy. Intel’s Itanium cannot run the 32-bit applications natively, and emulates the 32-bit environment, and makes them actually slower currently. There are also no real 64-bit tools or operating systems except a Microsoft Windows XP 64-bit for the Intel only platform but the AMD version of Windows 64-bit is coming later this year.

My personal suggestion if you want a 64-bit machine is to get the AMD so you can run your current 32-bit applications and gain performance in many cases at a low price of about the same as a 32-bit machine. Alternatively, you can wait and see how the industry solves the current two separate 64-bit platforms and hopefully one emerges so there are not multiple versions of the operating systems and applications. The future may be 64-bit, but it will take some time to see a clear safe path to it.

Remember 64-bit does not mean greater accuracy in most cases as AutoCAD has had 64-bit accuracy in the 32-bit platform for many years although some CAD systems such as Bentley just recently got the 64-bit floating-point accuracy, the 64-bit processors are really not needed for this ability.

Cheers,
-Shaan

Wow! Some Really Nice Architectural Desktop "ADT" Examples

Autodeskers Chris Yanchar and Julian Gonzalez of the Autodesk Architectural Desktop "ADT" team showed me some really nice examples of the power of their product. Of course I have to mention ADT is built on AutoCAD as a platform for the architectural specific industry.

You can find many awesome examples posted by ADT users in the discussion groups:
Autodesk Architectural Desktop Customer Gallery
Other discussion groups both web based and news reader and hopefully soon by RSS syndicated feeds.
http://discussion.autodesk.com
ADT Discssion group list where many ADT Team members also participate in the active discussions with cusomters.

Some Awesome Examples of ADT Users Work:

HOK S+V+E: Kansas City Stadium

HOK S+V+E: Kansas City Ballpark

HOK S+V+E Kansas City School Stadium

GEPA Bruneck: Italy

Wow!........

Cheers,
-Shaan

Free Plot Utilities for AutoCAD

Print contents of STB or CTB file Click Here
This tool provides a way to export a CTB or STB plot style tables to a comma-delimited text file. You can then import the comma-delimited text file into a spreadsheet program (for example, Microsoft Excel) and print the file or compare it with others. You can also print the text file directly.

CTB to PCP Converter Click Here
This tool provides a way to export a PCP file from a CTB plot style table.

Cheers,
-Shaan

AutoCAD 2004 Migration Utilities - For Free and also Very Helpful

Are you aware there is a free download of Migration related utilities for AutoCAD 2004?
Link: http://www.autodesk.com/migrationtools

The list of Migration Tools and descriptions:

Autodesk Batch Drawing Converter 2004
Autodesk® Batch Drawing Converter 2004 converts any AutoCAD or AutoCAD-based drawing file to AutoCAD Release 14, AutoCAD 2000, AutoCAD 2000i, AutoCAD 2002, and AutoCAD 2004 file formats. Autodesk Batch Drawing Converter allows conversion of pen widths to lineweights and the addition of page setups. Note: Autodesk Batch Drawing Converter 2004 is available in Brazilian Portuguese, Simplified and Traditional Chinese, Czech, English, French, German, Hungarian, Italian, Japanese, Korean, Polish, Russian, and Spanish.

Autodesk Customization Conversion Tools

For AutoCAD 2004 and AutoCAD 2004–based products (except AutoCAD LT), these Autodesk® Customization Conversion tools allow you to convert your customized menus, files, command aliases, and layer states, and they allow you to script with greater ease.

AutoLISP Compatibility Analyzer details AutoCAD 2004 compatibility issues found in AutoLISP® and Menu LISP files. When an issue is found, an explanation of the compatibility issue and suggestions on how to correct it are provided.

Menu and Toolbar Porter is designed to help you import your menus and toolbar items from previous versions of AutoCAD into AutoCAD 2004. You can also use this tool to add or remove menu and toolbar items from any AutoCAD MNU file.

Command Alias (PGP) Porter is designed to help you import your custom command aliases from previous versions of AutoCAD into AutoCAD 2004. You can also use this tool to add, replace, or remove command aliases from any AutoCAD PGP file.

ScriptPro takes AutoCAD scripting to a new level with an easy-to-use interface, logging, reusable project files, enhanced scripting with new keywords and utilities, and robust error recovery. Using ScriptPro you can apply a set of commands to multiple drawings by simply specifying a script file and the list of drawings that you would like to apply the script to.

Layer State Converter allows you to convert between the layer states created by LMAN (one of the AutoCAD® Express Tools) and the saved layer states introduced in AutoCAD 2000i software.

In order to use many of these utilities, you will need AutoCAD 2004 installed as they use some of the files from the installed AutoCAD.

Cheers,
-Shaan

Some Great AutoCAD Tips!

Saving Real Estate with Auto-hide feature for Palettes - Part 1
http://www.hyperpics.com/tipsandtricks/cad/autohide_palettes.htm

Saving Real Estate with Clean Screen - Part 2
http://www.hyperpics.com/tipsandtricks/cad/cleanscreen.htm

PEDITACCEPT and how it affects the PEDIT command
http://www.hyperpics.com/tipsandtricks/cad/peditaccept.htm

Cycling through the Layout Tabs in the drawing
http://www.hyperpics.com/tipsandtricks/cad/cycle_through_tabs.htm

3 ways to Accept changes and Exit the new Mtext Editor
http://www.hyperpics.com/tipsandtricks/cad/3_ways_to_exit_mtexted.htm

Using the QNEW command (Quick New Drawing)
http://www.hyperpics.com/tipsandtricks/cad/qnew.htm

Starting the session of AutoCAD with Template pre-loaded
http://www.hyperpics.com/tipsandtricks/cad/template_at_startup.htm

Tips Provided By:
Lee Ambrosius
HyperPics, http://www.hyperpics.com

Do you have some AutoCAD Tips to Share? Email them to me at shaan@autodesk.com with the email subject line of "AutoCAD Tips for the Blog".

Cheers,
-Shaan

Two Linetypes and/or Colors For a Dimension Using a CTB Plot Style in AutoCAD

I get this question at least a dozen times a year. The question is if you can have two linetypes or colors for a dimension. The most common reason is the person wants a solid baseline and a dashed or dotted extension lines.
This has been possible since AutoCAD 2000 and the addition of plot styles.

Sample DWF file showing two different linetypes and colors for the dimension.

You will need the free Autodesk View Express to view the DWF file.

JPEG Image of the DWF

Overview: In your Drawing, edit the dimension style and change the dim line, ext line, and text colors. Then set a plot style to redefine the way the two colors plot and display in a layout.

Step 1
Open the DIMSTYLE Editor and on the Lines & Arrows tab set the color for the baseline and extension line to separate colors. I chose green and red to clearly see the difference.
While still in the DIMSTYLE Editor navigate to the Text tab and set the color for the text. This is optional if you want the text to match a particular lineweight or color of the baseline for example.

Save the new dimension style as CONT-DASH-1

Step 2
Now lets create a color based plot style. Use the command for the plot style wizard R14PENWIZARD or from the menu Tools>Wizard>Add Color-Dependant Plot Style Table and select the option to create a new one from scratch. Name this plot style "multi linestyle dims" then choose next.

Step 3
Now select the button option to edit the plot style table. In the Form view, change the plot attributes for the colors you set for the dimension baseline, extension lines and text.
I select the color red and then set it to plot as blue with a .2 solid line.
Now select the button option to edit the plot style table. In the Form view, change the plot attributes for the colors you set for the dimension baseline, extension lines and text.
I select the color green and then set it to plot as blue with a .1 Dash Dot line.
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Step 4
Now make sure in the pagesetup for a layout you have the display plot styles enabled.

Your done.
Now you have a dimension style you can use on other drawings and output to DWF or the plotter.

Have an AutoCAD tip you would like to share? Email me shaan@autodesk.com

Cheers,
-Shaan

DWF Writer 2 Is Being Posted Any Day Now

The Free DWF Writer 2 which I mentioned the beta awhile back will be on the Autodesk web site very soon. When it is available I will post in here. It is a really nice Windows System printer driver to print to the DWF format from almost any Windows application.

Cheers,
-Shaan

Update: You can download the DWFWriter 2 from http://www.autodesk.com/dwfwriter

Very Cool Photo Gallery Software

I was reading Robert Scoble's (of Microsoft) Scobleizer Weblog and was blown away by the free travelogue-authoring tool tool developed by Microsoft Research. The tool World-Wide Media eXchange "WWMX" allows you to geographically stamp your photos allowing for a map showing on a map the location the photos were taken. I will try creating a sample gallery soon myself. what a way to show where you have been.

From the Scobleizer Weblog
"Cool Photo Travelog Authoring Tool
I was just over at Mick Stanic's blog, and saw that Microsoft Research's World Wide Media Exchange project released a travelogue-authoring tool that will allow you to create your own online travelogue out of photos, text, and optional GPS tracks. Check out Mick's "Melbourne xmas 2003" to get an idea of what you can do."

Cheers,
-Shaan

Do You Have What it Takes to be a Top Beta Site?

We really need some more of the really motivated and feedback driven beta sites.

I am always looking for AutoCAD beta sites that are willing to be very active and provide constructive feedback on ideas and features. We have thousands of beta sites but only small percentages are active and provide the feedback. We really need the feedback in order to make the right decisions and also become aware of issues and address them. Becoming a beta site does have many positives and some potential gotchas. I started as a beta site of Autodesk’s before coming to Autodesk in 1998. I was a well known "bleeding edge user". Some beta sites are only lurkers installing and just wanting to see what is coming up but we need more activity than that to make sure we are releasing the best products available.

If you think you have what it takes, make sure to fill out our long beta site profile as that is required of all beta sites. Click Here

Make a difference in the product and perhaps win great rewards for your feedback. Also communicate and exchange ideas with the developers and teams that create the products you love and use every day.

Cheers,
-Shaan

'Between The Lines AutoCAD Wish List'

In addition to the AutoCAD Wish List on AUGI.com I added my 'Between The Lines AutoCAD Wish List' & $100 Feature Survey. I will be reviewing these and also discussing the suggestions directly with the design and development groups periodically. I will also periodically take the top items and hold a voting to rank the top items.

'Between The Lines AutoCAD Wish List'

With the following survey you get to pretend you are the head of AutoCAD development. You get $100 to spend on certain features. This helps us see what are the most valuable potential future features.
Spend Your $100 Survey for AutoCAD

Cheers,
-Shaan

Online Autodesk® DWF™ Writer Video Tutorial by CAD-1.com

CAD-1.com has posted an online streaming video tutorial on the Autodesk® DWF™ Writer (http://www.autodesk.com/dwfwriter). They show how to use it and discuss uses for it to print from any windows application to the DWF format.

http://www.cad-1.com/tips&tricks_janfebvid-04.htm

Cheers,
-Shaan

Delete Layer Filters Fast with AutoCAD 2004

Prior to AutoCAD 2004, if you pasted a block or inserted into a drawing the layer filters from the block would also come along. In some cases the drawings would get quite a few layer filters. Customers pointed out this problem and we changed the behavior in AutoCAD 2004. No longer do layer filters come in with blocks whether pasted or inserted. Also you can easily now select or delete all filters in the drawing. No more need for a custom LISP to do this.

We Listen

Cheers,
-Shaan

Shawn Caldwell Posts His Autodesk University Photos

Looks like Shawn Caldwell had a blast attending Autodesk University this year. See his online photos.
Click Here

Shaan's AU 2003 Photo Gallery
Click Here

Cheers,
-Shaan

The Solar System on a 10,000" X 10,000" DWF

I actually just for fun created a high DPI multiple page DWF of the Solar System on a 10,000 inch by 10,000 in page size. It was only 34KB in size. I set the plot style to make all lines with 0.0" lineweight for more crisp lines.

I placed the DWF file for viewing Click Here

Please note you will need the free Autodesk Express Viewer 4 to view this DWF.
Download the Free Viewer Here
More about DWF HERE

Cheers,
-Shaan

Load ARX Files Automatically

Did you know...
If you create a text file named acad.rx in your Autocad directory, you can list your ARX files in this file and then when AutoCAD loads it will automatically load the listed ARX files?

Cheers,
-Shaan

DWF Precision Article by Brian Mathews of the DWF Team

DWF precision

One of the advantages (to some customers at least, maybe not you) is the security offered by DWF because it has the same restrictions as physical paper.  Many users don't want people stealing their model data.  Let me explain:
 
When you take a measurement in AutoCAD from a DWG file you have a 64-bit double-precision floating point value that gives you extreme levels of precision and accuracy.  You also have lots of model intelligence.  For example an ADT door knows it is a door and the wall knows that it needs to have a hole to contain the door and that the framing inside the wall needs to adjust based on the position of the door.  The door and walls aren't just pictures made of lines, they are intelligent objects with cross-linked relationships.
 
With physical paper and a physical ruler we all know there are limitations to the precision and accuracy; we all know you only have are a bunch of dumb pixels (the model intelligence is gone).
 
The DWF files you have today are essentially electronic plots, generated from AutoCAD's (or another application's) plot engine.  As such many of the same limitations apply to DWF as to paper.  This is where the security comes in: since the DWF doesn't have the same precision and accuracy, and since the DWF geometry is tessellated (blocks and objects get exploded into their individual graphic strokes) it isn't easy to turn a DWF back into a DWG (just like it isn't easy to turn paper into a DWG).  Even if you did the work to change the paper or DWF back into a DWG you'd be missing lots of model intelligence.  Many customers feel that physical-paper is sufficiently secure and they want that same level of security with DWF.
 
So why are your measurements not 100% accurate/precise with DWF?
 
By default AutoCAD 2004 generates DWF files at 400 dots-per-inch on whatever virtual paper size you are plotting to.  If you plot to 8.5x11 inch paper, that means in the horizontal dimension there are only about 4,000 dots or coordinates that the DWF lines can terminate at.  This effectively limits the precision of any measurement.  If your drawing represents a 300 foot long building, and if that floor plan (after you account for margins) is filling about 66% of the width of the page, that means there are only 4,000 * .66 = 2,640 dots at which the lines can end at.  This means that our precision is the 300 feet / 2,640 dots = 0.1136 feet (or 1.36 inches).  Wow!  So if I use the default 400 DPI on small 8.5x11 paper I can only take measurements that are accurate to within about 1 inch!  This is much less precision than AutoCAD (which can measure features smaller than an atom!).  Also note that the DWF in this example is actually HIGHER precision than what you would be able to do with a ruler and physical paper.
 
So how do I improve the precision?
 
The analogy is the same for DWF as it is for paper.  With paper if the author wants consumers to be able to make better measurements what do you do?  You print to larger paper (or you buy an electron microscope)!  If I make my 300 foot building and print to E-sized paper rather than Letter-sized, the result is better precision both with physical paper and for DWF (since the DWF will be using the same 400 DPI times a lot more inches of virtual paper which means there are a lot more dots).
 
But what do I do if I want to allow higher precision without changing the paper size (since my printer only prints to a specific paper size, that is the size I have to use)?
 
With physical paper you don't have many options here.  You could get a higher resolution printer (1000 DPI rather than 300 DPI for example), but it is still hard to get additional precision when using a ruler and the human eye.  For the most part you have to go to a bigger paper size to get higher precision measurements with physical paper.
 
With DWF you can leave the paper size alone (at 8.5x11) and change the DPI setting (in the plot options custom-properties dialog).  You can set this DPI up to a much higher number (the DPI times the paper width must be less than 2^31 which is 2,147,483,648).  If you used the maximum precision of DWF (which is still a lot less than for a DWG which uses 2^48) you can get great precision in your measurements.  For example: for 8.5x11 paper we could set the DPI in AutoCAD 2004 to be 195,225,786 DPI (try that with your laser printer!).  In our example above if you crank the math out you'll find that you can measure your 300 foot building down to 0.000028 inches!!  When was the last time you needed a measurement accurate to one-10,000th of an inch??

Let’s also consider a GIS mapping example. DWF has a maximum precision of 2,147,483,648 total dots when you increase either your DWF DPI or your DWF paper size (or a combination of both). If we say the continental USA is about 3,000 miles wide at what precision can a DWF resolve a map of the USA? Well that’s just (3000 mi * 5280 ft/mi * 12 in/ft) / 2,147,483,648 = 0.089 inches. In other words when making a DWF that represents the entire continental USA we can resolve objects down to a precision that is about 2.3 millimeters in size! Not many people need precision that high! However, if you use the default AutoCAD DWF precision of 400 DPI on an E-sized sheet of paper you’d only be using 14,400 out of the available 2,147,483,648 DWF dots and thus you’d only be able measure the USA down to +/- 1,100 feet.

I increased my DPI value very high but my measurements still aren't perfect. Why?
 
The paper size and the DPI setting are only part of the story.  That determines the absolute maximum possible precision that is available.  However, other factors influence the precision of your measurements.  For example, when you measure between two line endpoints, where exactly are you measuring between?  Remember that lines have width and they have end-caps.  As such they have volume.  Since some types of geometry become tessellated in the DWF file and many types have volume, the auto-snap technology sometimes can't tell exactly what piece of tessellated geometry or which part of the volume you are wanting to measure from.  For the line case, are you measuring from the line endpoint or from the edge of the line-cap semi-circle that extends past the endpoint?  Also, the auto-snap technology in certain cases may depend on the resolution of your screen (the mouse can only point at a particular screen pixel) and there are very few pixels on a screen.  Furthermore, the DWF coordinates have to pass through multiple coordinate transforms.  Each transform introduces round-off errors and precision errors which accumulate. For most drawings these issues are so extremely small that you can ignore their effect.
 
Summary:

To get better measurement precision:

The author must intentionally enable you to receive the extra precision as part of the security concept.

The author can increase the size of the virtual DWF paper.

The author can increase the DPI setting of the DWF driver to use more pixels and precision.  Increasing DPI will increase the DWF file size, so you don't want to use a crazy DPI.

Plotting without line weights or other settings that lead to tessellation *may* improve the precision (but this depends on a complex set of variables and may not change the precision at all).

DWF can measure the continental USA with a precision of +/- 2.4 millimeters when using the maximum DPI and paper size settings

http://www.autodesk.com/dwfit

Brian Mathews
 Autodesk, Inc.

More from the AutoCAD Accuracy Universe and the Floating Point

AutoCAD's 64-bit precision has been discussed and documented for years and hailed as the most technically precise system for many years since the eighties. This was long before people realized that some would actually need even more precision in the floating point calculation provided by the then math coprocessors and then in the 32-bit platform. There was an example demonstrated by Jon Walker the founder of Autodesk with a AutoCAD drawing showing a to scale of the universe. In this drawing of the universe you could zoom in on the moon and see a moon lander with a plaque and text on it. The drawing has many named views for the locations in the solar system and I have resaved it in AutoCAD 2004 format.

Screen capture of the solar drawing. All images can be clicked on for a larger version in a pop up window. You can also download the drawing from Here

To demonstrate the limitations of the 64-bit floating point I created a polyline with an arc (bulge) next to the moon lander plaque. Now because we are 1.499E+08 (149900000.0) from 0,0 or located at the coordinates of X=-1.205E+08 Y=8.921E+07 if we try to offset this polyline the small radius bulge will round to 0 due to the limit of digits in the floating point of the processor for calculations. So the limitation is if you have an object a very great distance from the origin coordinate of 0,0 the limit of 15-16 digits calculations could result in unexpected results. Of course by simply moving this object temporarily closer to the origin of 0,0 the offset works perfectly because less digits are used in this calculation and no rounding issues.

Screen capture of the polyline near the plaque.

Screen capture of the polyline after Offsetting .0001 and the unexpected result.

Screen capture of the polyline after Offsetting when the plaque and polyline were moved to 0,0 at the center of the sun. The offset is as expected and correct.

What does this all mean?
If you are designing a small micro circuit board on the surface of mars, move the part closer to the 0,0 when using operations that require system calculations such as Bhatch, Offset, and so on. Well AutoCAD uses the most precision it can and has since the eighties but with new technology in processors coming we will continue researching to see if we can get even more precision in the extreme conditions.

Explanation on the accuracy by the late (and greatly missed) Alex Januszkiewicz

Sincerely,
Shaan Hurley

Welcome to CAD Industry writer Ralph Grabowski to the world of blogs

Welcome aboard the blogging phenominon with WorldCAD Access - Talking about CAD. I would like to think including my blog link in an email before Christmas may have inspired you in some simple way to look at the technology.

What will happen to the weekly email ezine UpFront eZine?
I surely would not want to lose either option. I look forward to checking your blog by visiting and also with an RSS aggregator when you get around to enabling a RSS feed. Imagine your new slogan "On your desktop, within a minute, piping hot and fresh CAD News".

Sincerely,
Shaan

Back to work.

Well my holiday vacation is now officially over and it is back to work I go. I had a great holiday and look forward to a great new year of exciting projects.

Interesting Link:
Raw Photo feeds from the NASA Mars Exploration Rover "Spirit"

Panoramic Image from Mars

Cheers,
-Shaan

More on 64-bit Processors and AutoCAD

I am posting more on the 64-bit CPUs that are slowly coming to market from both Intel & AMD. I mentioned the AMD Opteron and the increased performance with standard AutoCAD 2004 in my post to this blog on October 25th 2003 "64 bit Computers & AutoCAD". I was hoping that the 64-bit platform would offer a 128-bit double precision floating point allowing for 30-32 digit double extended precision. Unfortunately it does not in either the Intel or AMD processors that have been announced to this date.

The IEEE-754 and 854 standards specify the numeric formats, value sets, and how the basic floating point arithmetic works.

AutoCAD Currently used 64-bit precision and has since the early 80s. No other known CAD or geometry kernel I know of exceeds this 64-bit precision and a few CAD systems just recently got this level of precision after the year 2000 about 15 years later than AutoCAD.
The current 64-bit Precision Limit: Double-precision format – 64-bit data width, 15 to16 digit precision
1,000,000,000,000 to 0.0000000000000001
Normalized as 53 bits of significance 1 bit sign 10 bits exponent

We have been researching the implications of going to the maximum allowed by the 32 & 64-bit processors which is 80-bit. It may change the DWG and also affect many other core functions
Extended-precision format: 80-bit data width, 18 to 20 digit precision
Normalized as 64 bits of significance 1 bit sign 15 bits exponent

In the AMD Opteron there is 128-bit XXM registers, but you do not get 128-bit precision. You get two 64-bit doubles at the same time which is normalized as 53 bits of significance.

In the Intel Itanium the native floating point is 82-bit which is normalized as 64 bits of significance.

But with the 64-bit Operating Systems we do get a larger addressable memory beyond the current 3gig which would allow larger models for example. But that means a total recompile to the 64-bit platform which is a huge undertaking. Also the Operating Systems and compilers have not all been released.

It is my own opinion that a true 64-bit port of a CAD application will be some time down the road, maybe years when the market adopts a standard and there are compilers, Operating Systems, and also available 3rd party libraries which many CAD applications depend on such as g