Tag Archives: reference

Determining the length of a curve in Corel Draw 11

2012-06-21

When designing in Corel Draw, it can be very useful to know the total length of a curve. Since the curve may consist of straight and curved sections, this is not trivial, and unfortunately the user interface doesn’t help you here – it only tells you the width and height of an object.

So in order to get that length, use this Visual Basic macro:

Sub getLineLen()
 Dim sel As Shape
 Set sel = Application.ActiveDocument.ActiveShape
 Dim l, sl As Double
 Dim seg As Segment
 Dim prevu As cdrUnit

 prevu = Application.ActiveDocument.Unit
 Application.ActiveDocument.Unit = cdrMillimeter

 For Each seg In sel.Curve.Segments
 sl = seg.Length
 l = l + sl
 Next seg
 MsgBox ("Length: " & l)

 Application.ActiveDocument.Unit = prevu
End Sub

This should work in other versions of Corel Draw, too, but I could verify that for version 11 only. In order to make this work, go to the menu item “Tools -> Visual Basic -> Visual Basic editor…”. Click on “GlobalMacros”, then on “Module” and “CorelMacros”. Paste the code at the bottom of this text file. Then click on File -> Save.

To use the macro, select the relevant curve, then click on “Tools -> Visual Basic -> Execute…”. Select the macro from the list (select “Macros in” “all standard projects”) and click on “Execute”. The length of the curve will appear in a small message box.

Red lines (unconnected edges) in Pepakura

2011-06-05

I work with the combination of Blender and Pepakura for creating paper models. Sometimes it so happens that a seemingly perfect model in Blender has unconnected edges in Pepakura. These show up as red lines and result in a model where two faces are not connected although they should be.

There are several causes. One is that one or more vertices are duplicated, i.e. that two vertices are positioned at the same location. To fix this, go into Edit Mode, then press A to select all vertices, then press W and “Remove doubles”.

If that doesn’t help, in Edit Mode press ctrl+alt+shift+M. This selects non-manifold edges, i.e. edges where the model is open. Then press alt+M in order to merge the affected vertices.

If the problem still persists, you can recalculate the normals. Go into Edit Mode, select everything (press A), then press ctrl+N. The problem in this case is that each face of your model has an orientation. You can think of it as the “front” and “back” of the face. The so-called normal is a vector perpendicular to the plane of the face. Since the face has two sides, the normal can point in either of two directions. If a model consists of a contiguous surface where the normals of some faces are oriented differently than those of the other faces, Pepakura assumes that the surface isn’t actually contiguous (and rightly so).

In most cases, ctrl+N solves this problem automatically. However, there are some models which do not enclose a space completely, but which contain openings. In such a case, Blender may fail to orient all faces properly. You will see the problem in Pepakura by two sets of faces, one showing the texture (or face color) on the “outside”, and one showing it on the “inside” (double quotes, as technically there is no such thing as in and out for a model with openings). You can switch the orientation of the normals manually in Blender – here is a tutorial.

From Blender to Pepakura to Corel Draw to CraftRobo

2011-05-08

Blender is an excellent open-source 3D modelling application. Pepakura Designer (short: Pepakura) is a very useful tool for papercrafting, which converts 3D models to 2D templates which can be printed on paper, cut and assembled into the original 3D model.

The two are a great combination for papercrafting. In fact, I found the combination of Blender for 3D modelling, Pepakura for unfolding, Corel Draw for postprocessing, adding artwork and finetuning, and finally CraftRobo for cutting perfect. Here is the complete workflow:

First, you need to export the Blender model to the 3D Studio format understood by Pepakura.

Go to

File > Export > 3D Studio

then save the file. Then, simply open the file in Pepakura. Once you have created a satisfactory 2D pattern, the next step is to get it into Corel Draw. There are several vector export formats available in Pepakura, however all of them have some problems. I found the best one to be DXF (AutoDesk’s ‘Drawing Interchange Format’).

In Corel Draw, click on

File > Import

then select ‘DXF AutoCAD’ as file type and select the file exported from Pepakura. You will then be able to place the file into your existing page, by pressing LMB and dragging the mouse until the shape has the correct size.

Note that the DXF format separates the shapes for folding and cutting into different layers, which are preserved in Corel Draw. This is very convenient when you want to process them differently (such as assigning them to different cutting types for the Craft Robo).

One important drawback of the DXF format is that Pepakura chops up the outline of a shape into individual edges. This can be difficult to work with in postprocessing. Therefore, another option is to use the EPS format. Here, you need to carefully c0lor all cutting edges in the same color in Pepakura. This will create a contiguous outline in the EPS file. Unfortunately, the EPS file does not preserver the color information itself, so all edges – folding and cutting – are black, and you have to separate them manually.

You can now add artwork and edit the shapes, if necessary. Once that is done, you can simply send the file off to the Craft Robo for cutting. I keep the folds and cuts in different layers (see above) and assign the following cutting parameters:

Folds: Index 90lbs paper, 10cm/s, force 30, line type: Custom 1 (0.120 cm a, 0.120 cm b), Passes: 1

Cuts: Index 90lbs paper, 10cm/s, force 30, line type: 1, Passes: 2

Converting AVCHD files to MPEG-2, MPEG-4, AVI or WMV

It so happens that my Panasonic GH-1 is capable of spitting out so-called AVCHD files (with the extension .MTS). AVCHD is supposedly superior to older video encoding formats, but a lot of old software (such as Adobe Premiere Elements 3) cannot process it.

Being a strong proponent of not touching a working system, and seeing that Premiere Elements 3 still works quite well for me (except for, ahem, AVCHD import), I looked for inexpensive ways to convert such files to MPEG-2. And, lo and behold, I was successful:

There is a freeware that does the trick quite neatly, the aptly called Free-HD-Converter. Now, be careful: This piece of software is indeed free, but during installation it tries to install rather spammy looking browser toolbars. I unchecked these options (one cunningly starts with ‘accept terms and conditions’ … of the toolbar, that is).

If you avoid these toolbars, everything else seems rather fine. The user interface is very straightforward, there are several options with regard to the output format, and that’s about it. Conversion is taking some time, on my (admittedly rather old) system, the conversion frame rate is about 3 fps, which means that one minute of video takes about 10 minutes to convert.

Lego Group’s fair play

2011-02-23

Among other things, this site contains templates that can be used in conjunction with Lego® toys. The Lego Group is rightfully protective of their trademarks, and for anyone providing stuff related to Lego® bricks, it’s a good idea to follow their fair play rules. I usually despise all documents in legalese and am very easily annoyed by overzealous corporations, but in this case I have to say that the Lego Group did a good job in making their point clear, helping fans to play along, and to keep things very reasonable.

Since I require it for all posts related to Lego® bricks, I will here copy their suggested disclaimer:

“LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this site”

Printing and cutting the templates of this site

2011-02-20

This site features several models which can be printed and cut. You have three options:

  1. Print a model, then cut it manually
  2. Print a model, then cut it using Craft Robo
  3. Import the artwork and cutting outline into a software for whatever cutting plotter you use, and proceed as required.

Option 1 is self-explanatory, for option 3 you are on your own, and for option 2 I do have further instructions here:

The templates come in two parts. Download the PDF and the GSD file. The PDF contains the artwork, the GSD contains the cutting instruction for the Craft Robo.

Print out the PDF onto a 190g crafting paper. Load the paper into the Craft Robo, then load the GSD into Robo Master and start cutting.

Using the SVG files

SVG is a universal file format understood by many vector graphics applications. One of the most popular open-source vector editors is Inkscape. In addition to the actual artwork, the SVG file contains green and magenta lines. Green lines are supposed to be cut, magenta lines are folds (which should be cut as a dashed line, preferably using an alternating pattern of 1.2mm cut and 1.2mm non-cut).

Using the Corel Draw files

The Corel Draw files are actually the easiest to use. They contain everything you need in order to print and cut a model. Just print the page after loading a file, then cut it using the Corel Draw macros that came with the Craft Robo software (the menu item “Cut/Plot Craft Robo” under the button “Launch application” in the tool bar (the icon looks like the Corel logo with a dropdown arrow).

The “Cut/Plot” dialog will open. Make sure you check “use registration marks”. Also, select “By layer”, then uncheck the “Art” layer. Check the “Fold” and “Cut” layers. Check “Enable driver options”, uncheck “single setting for all”. Select the appropriate paper for both layers (Index 90lbs works for me, using 190g paper). For the “Fold” layer, select line type “Custom 1″, for the “Cut” layer line type 1.

Edit line type “Custom 1″, and enter “0.120 cm” for ‘a’, “0.120 cm” for ‘b’. This will produce dashed lines for the folds. Depending on your paper type and thickness, you may want to set the “Cut” layer to two or more passes instead of just one.

Converting CorelDraw to GSD files

2011-02-19

Craft Robo’s aptly named control software Robo Master uses a proprietary file format ‘GSD’. I work with CorelDraw, and while CDR is perfect for cutting directly (and in my opinion much better suited for complex Craft Robo projects than Robo Master), there is no way around the GSD format if you want to pass on designs to other people.

The way I do the conversion is as follows:

First, I split the art to be printed and the cutting outlines. The art to be printed goes into a PDF file, and the cutting outlines into a GSD. The reason behind this is that complex artwork does not convert correctly to GSD – only very simple shapes do.

Now, in order for this to work we need to make sure that the registration marks are included in the PDF and that they align with the registration marks used by Robo Master.

I have prepared a Corel Draw file with registration marks at the exact same positions as the default positions in Robo Master.

Using this file, these are the steps I follow:

  1. Position the artwork and cutting outlines inside the registration marks
  2. Move the cutting outlines to an invisible layer or delete them temporarily
  3. Export the document as a PDF
  4. Make the cutting outlines visible again or restore them. Delete everything else (make sure that the cutting outlines are ungrouped and are all in a single layer. This should be the only layer in the document)
  5. Due to a bizarre behaviour of Robo Master, where imported DXF files have their center at the lower left corner of the page, we need to add an offset to the outlines. Go to ‘Arrange-> Transformation -> Position’, and enter 148.5 and 105 mm (half the page size for an A4 page). I have prepared a macro included in the template mentioned above you can use for that: Go to “Tools -> Visual Basic -> Play” and select RecordedMacros.dxfoffset
  6. Now go to “File -> Save as…”, select as file type ‘DXF – AutoCAD’
  7. In the AutoCAD export window, select “AutoCAD R13″ as the export version, and select “Millimeters” as the export unit.
  8. Open Robo Master, go to “File -> Load DXF…”
  9. Save the file as a GSD file.

Paper weight and measurements

2011-02-17

Ok, so this is one more thing where the shadow world government has failed miserably: Paper weight (technically, grammage) and dimension units, or – even worse – paper size standards. There is the big divide between continental Europe and the British empire, including its overseas colonies, but then there is also a whole mess of local customs, regional deviations, and odd preferences.

It seems nobody can agree on what size paper should come in, and how to measure its dimensions. Luckily, here is a convenient table for everything, and here is the Wikipedia article on the same topic.

Most projects described on this website will be based on190g-300g DIN A4 paper, which corresponds to 53 -82 lb bond/ledger and 8.27″ x 11.69″.  Using US letter format should be fine, but you should slightly scale the templates to fit on the page before printing. If you are unsure about the grammage, just use sturdy carton which is still flexible and thin enough to be easily cut and folded.

If you use a Craft Robo, you have probably already found the thickest paper you can still cut through, and that should work fine for the projects on this site. If you are unsure about what the Craft Robo can digest, I suggest that you do some quick experiments. Note that there is a huge difference between a sharp new blade and a blade that has cut through a couple of dozen sheets already, so try to use a fresh blade.