AutoCAD

DWF: The Saga Continues, Part 2 (Learning Curve AutoCAD Tutorial)

1 Jun, 2007 By: Bill Fane

AutoCAD's DWF files are easy to set up.


Once upon a time, a short while ago, the people of Vancouver rejoiced. The three-day drought had broken, and the rains had finally come.

Okay, so it rains a lot in Vancouver, B.C., but on the other hand we don't get hurricanes, tornados, searing heat, freezing cold and major blizzards. We have terrible weather but a great climate. It's been said that we don't tan; we rust.

Isn't this where we came in last month, with Captain LearnCurve complaining about the rain?

Yes, which is why it is a perfect segue into this month's topic, which is a continuation of last month's article about DWF files.

Last month's "Learning Curve" showed that the DWF file format lets us create a lightweight version of an AutoCAD drawing file. As such, it has all the advantages and disadvantages of a piece of paper.

Recipients can open DWF files, pan and zoom, freeze and thaw layers, plot and mark up, but they can't edit any content and they can't save their changes other than their mark-ups. Like paper plots, they are a read-only format. You can thus supply full design information to the recipient, but they don't have access to modify or copy any of the design content.

Two Ways to Create a DWF File
Okay, I lied. There's really only one way, but there are two ways of getting there.

The first way is to simply use the standard Plot command. Instead of using a hardware printer, however, just select DWF6 ePlot.pc3 as the plot device. You can then specify most of the usual plot parameters, the most significant of which is the paper size.

The recipient can't zoom into the same extremes as they can with the original DWG file. The DWF file contains no more detail than an equivalent paper plot. If you want to send finer detail we need to DWF (hey, if "to Google" is now a verb, why not "to DWF") to a larger paper size.

Here are two examples that demonstrate this idea. In each case I started with the same DB_SAMP.DWG I used last time. It's a nominal 1:400 scale.

I DWF-ed it twice, once to A-size paper and once to E-size paper. I then opened each DWF file with Design Review and zoomed into the same region. The conclusion is that DWF-ing to a larger paper size produces more detail.

figure
A portion of a large drawing that was DWF-ed to A-size paper.

figure
Here's the same portion of the same drawing, DWF-ed to E-size paper.

Interestingly, the text retains the same level of detail when it's Mtext, but not when it's an attribute.

Not unexpectedly, specifying a larger paper size results in more detail in the file, both when displaying in and printing from Design Review.

There has to be a downside here, of course. The more-detailed DWF file must be larger than the less-detailed one. Let's take a look at the numbers to see just how much larger.

Original DWG = 242kB

A-size DWF = 42kB

E-size DWF = 44kB

Interesting! The E-size DWF is only marginally bigger than the A-size one! Let's go a step further. I set up the DWF6ePlot.pc3 plot device to include a new custom EE (68" X 88") paper size. The DWF file only increased to 47kB.

In a manner similar to the two previous illustrations, when I printed the full EE-size DWF to an A-size paper I got a much sharper, clearer print than when I printed the A-size to an A-size.

It seems that there is a huge advantage in greater resolution from a larger sheet size, but only a marginal downside in file size.

On the Other Hand . . .
The other way to produce a DWF file is to use the Publish command, as I introduced last month. It brings up a dialog box that lets you specify a number of additional parameters.

figure
The Publish command gives you many options when creating DWF files.

The first thing to notice is that this isn't specifically a DWF function -- it's more a generic "publish" capability. You can publish to the plotter named in the page setup or to a DWF file.

Next, you can specify different page setups. This capability can be very useful when working with DWFs, so let's take a look at it. Cancel the Publish dialog.

To begin, start the PageSetUp command (File/Page Setup Manager), which brings up the Page Setup Manager dialog box.

figure
Use the Page Setup manager to create and modify page setups.

Click on New. When the New Page Setup dialog box appears, enter a suitable name for the new setup and pick a Start With choice. Click OK. Surprise! Instead of returning you to the Page Setup Manager dialog box, it switches to the Page Setup dialog box that looks almost exactly like the Plot dialog box.

Now, specify any of the plot details you want. For our purposes, use the DWF6ePlot.pc3 device. Set the paper size (bigger is better), the plot area, the scale and so on.

Click OK to return to the Page Setup Manager and close it.

You can create multiple page setups, based on both physical plotters and the DWF device. Now, whenever you plot, you can simply apply a page setup to quickly flip between page setups.

Okay, back to the Publish dialog. Click on the Page Setup/3D DWF box for a specific sheet and then select the desired page setup. This step automatically switches the plot device, paper size, scale and so on to the specified setup. You may want to remember this fact for regular plotting from alternate setups as well as for DWF-ing.

Now you see what I mean when I said there are two ways to DWF, but in fact the Publish command is basically another way of getting to the Plot function.

The More the Merrier . . .
You may recall that in last month's "Learning Curve" I had you delete the paper space layout from the sheet list. Well, this time try Publishing the same file without deleting the paper space layout. Open the DWF file with Design Review and observe the Contents region in the upper left corner. It shows both the model space and paper space areas of the drawing. Click on the appropriate one to have it display in the viewing area.

But wait, there's more! A single DWF file can contain any number of layouts, and they can come from more than one DWG file. Go to the Publish dialog box and click on the Add Sheets button Add Sheets Button. You can browse to any drawing file and select model space and any desired paper space layouts from it to be included in a single DWF file. The only requirement is that any selected sheets must have a page setup initialized for them. Better yet, you can mix and match DWF plots and paper plots in the same set.

A bit of experimenting also reveals that you can save and load the list of sheet sets, so you don't need to browse over and over whenever you want to republish the same set.

The Plot Thickens . . .
If you're working in a drawing that contains 3D solid objects, you can specify 3D as the page setup in the Publish dialog box. When the DWF is opened in Design Review, a number of 3D options become available, including shade and wireframe view modes, section slicing and so on.

By default, the 3D option produces coarse objects wherein curved surfaces are composed of a series of flat facets, not unlike a disco mirror ball. This can be improved by changing the drawing's 3ddwfprec setting from the default of 2 to the maximum of 6, but this time there really is a downside:

3D DWG = 49kB

3ddwfprec = 2 then DWF = 6kB

3ddwfprec = 6 then DWF = 895kB

It's getting late, so let's shut down for now. Be sure to come back next time when we I'll explain how to apply redlining and other mark ups to a DWF and then how to inhale those markings back into the original DWG file.

And Now for Something Completely Different . . .
Replacing the radiator and shutter assembly in a 1937 Rolls-Royce Phantom III can be very awkward. It's a heavy contrivance, weighing in at roughly 180lb. It sits on a steel plate, which in turn is bonded to a thick rubber pad. Your must guide two 1/4" diameter mounting studs on the bottom of the radiator assembly through two holes in the plate. The problem is that there is a loose 1/4"-thick steel spacer plate with two matching holes that goes between the bottom of the radiator and the mounting plate. It's nearly impossible to get everything lined up without the spacer shifting its position, so the trick is to use double-sided carpet tape to hold the spacer plate to the bottom of the radiator during the operation.


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Lynn Allen

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