John -

Thanks for your encouraging feedback.

Will the Archimedes Spiral tool provide what you are after? Using the interactive tool, you can enter two radii to establish the rate at which the diameter of the spiral grows and set the height parameter to specify how tall you want the spiral to be - essentially giving you a tapered helix. See attached figure.

The Archimedes Spiral option in the dialog box off the Plugins menu offers still more control because it lets you specify the radius at each of two particular numbers of turns - the first and the last in your case.

Thanks to Michaelv for identifying a rather ugly "undocumented feature". The catenary and parabola logic was getting confused when the model units was something other than inches. Need to have a little talk with the QA department about that one.

I have also incorporated the suggestion of adding toolbar.restore to the appropriate scripts.

Unfortunately, Andrew, I don't have toolbar icons for the catenary or the parabola at this time.

The Curve Maker plugin has been updated to include more interactive drawing and editing options.

You can now draw and edit a catenary, parabola, sine or cosine curve interactively.

It's pretty much like using the rectangle tool as shown in this example video
http://www.youtube.com/watch?v=M4QUO0PaI_E

You can download the updated plugin from here:
http://www.drawmetal.com/download

The VCB Calc plugin has been updated and can be downloaded from http://www.drawmetal.com/download-vcb-calc.

In this version, you can extend a previous calculation by entering an operator as the first character after a Result has been obtained.

Also, 'g' is now a reserved word standing for the Golden Ratio. [Due to the differences between the PC and Mac versions, this is a Mac only feature.] For example, entering 3.5 * g = in the VCB (Measurements) box yields the Result 5.6631.

Edited Post:

Version 1.2 of the Draw Metal plugins has been further updated to 1.2.1 and can be downloaded from http://www.drawmetal.com/download.

Many thanks to hebeijianke for providing the Simplified Chinese translation. Accommodating Simplified Chinese uncovered some shortcomings in the way translations were handled, so anyone using any translation is advised to install this version.

More details are available in the Release Notes:
Release Notes 1_2_1.pdf

Original Post:

Many thanks to Oxer for providing the Spanish translation and Christophe Plassais for the French translation.

Curve Maker now supports entering parameter values for the underlying mathematical equations to specify a curve. Once a curve has been drawn, its' parameters can be edited and the curve will be redrawn. The equation options for Archimedean, Bernoulli, Sine and Cosine include exponentiation parameters to enable generalizations of these curves to be drawn. Parameters also include Rotate, Flip and uniform Scale options. While you do not need to know any formulas, a basic understanding of math is helpful in using this approach for drawing a curve.

Using the parameter approach, you can now draw four more curves: the catenary, Cotes spiral, the hyperbolic tangent spiral and the hyperbolic cotangent spiral.

Taper Maker now supports more path positions (“lower left”, “lower right”, “upper left” and “upper right”)

VCB Calc is a tool that computes the value of simple arithmetic expressions entered in the VCB. You can download it from http://www.drawmetal.com/download-vcb-calc. Instructions on how to use the tool are available here: http://www.drawmetal.com/use-vcb-calc

The major features of the tool are:

• Adds, subtracts, multiplies, divides and raises to a power.
• Understands length, area and volume and their relationships.
• Works with all standard SU units of measure (" ' mm cm m).
• Click on an edge or a face in a model to use it's dimension in a calculation.
• Uses the Ruby Console as a virtual "paper tape".
• Observes format preferences on the Units tab of the Model Info window and displays results in multiple formats.
• Accepts international decimal separators.
• French version available.
• Stores results in user-defined variables (named memories) [largely a Mac only feature].

For example, entering 3" * 2 / 25.4mm = in the VCB yields the result 6 in the VCB. Entering 50"2 / 10" = yields the result 5". Entering 10"=mm yields the result 254mm.

As an example of creating user-defined variables, suppose we wanted to divide 5 square meters by 10 centimeters and store the result in a variable named a. This can be accomplished by entering 5m2/10cm=a in the VCB. At least this is possible on a Mac, but not on a PC.

The reason is that SU intercepts keyboard shortcuts differently between Mac's and PC's. On a Mac, only the first character of an expression entered in the VCB is subject to being interpreted as a shortcut. On a PC, the "a" at the end of the expression 5m2/10cm=a is seen as the keyboard shortcut for the Arc tool.

Clearly, this limitation makes the tool a lot less useful/interesting on a PC than on a Mac. It makes it impossible on a PC to evaluate something like a + b = c.

Many thanks to Gaieus, thomthom, TIG, and Jim for their insights and suggestions. Also, several beta users provided very valuable comments and feedback.

So far, the only time the toolbar icons have not worked is when they had not been installed in the right place in the file hierarchy. After installation, the file hierarchy for the plugin should appear as shown in this figure.
toolbar_installed.pdf

Fredo -

@unknownuser said:

One question: do you know if mathematically you can extend the Cornu curve to a suite of control points in 3D space (i.e. not in a plane)?

Sorry to be slow in responding. The mathematical extension to 3D is discussed in Chapter 11 of Raph Levien's forthcoming PhD thesis (http://levien.com/phd/thesis.pdf). That does not imply, however, that I will be programming such an extension.

OK, the irritating sound mystery is solved.

Some example code I had used featured a UI.beep which I had not noticed, and the machines I use have the alert sound muted.

I have updated the download code at: http://www.drawmetal.com/download

Sorry for the inconvenience.

Dave -

Thanks for reporting this problem. There is nothing in my code that wants or seeks to make a sound, and it doesn't happen on my machine. Let me see what I can find.

Terry

The latest versions (1.1) of the Curve Maker, Taper Maker and Stock Maker plugins are now available here:
http://www.drawmetal.com/download

All current users are encouraged to install it. SketchUp 7 is required to use the new interactive features.

The major enhancements are to Curve Maker:

1. New interactive tools for drawing the following spirals: Archimedes, Bernoulli (aka logarithmic or equiangular), Euler (aka Clothoid or Cornu), Fermat, Golden, Helix, Hyperbolic and Lituus
   

This brief (3 min) video provides information on how to use these tools: http://www.youtube.com/watch?v=JW7VyVvSiwY

2. The capability to draw Cornu splines. This tool draws a smooth curve that passes through a given set of points. For example, the Cornu spline on the left in the figure below passes through the endpoints of the line segments shown on the right.
   

You can use an existing line as the basis for creating a Cornu spline or you can draw a Cornu spline interactively. You can also interactively edit a Cornu spline.

This tool is computationally intensive. Larger values of the parameters that control the algorithm (i.e. iterations of 100, 200 or more and sides/segment of 50, 100 or more) produce nicer curves but at a computational price. In practice, you probably want to use smaller values when drawing interactively (i.e. iterations = 50, sides/segment = 20). You can always go back and edit the algorithm parameters to draw a smoother curve.

At the 1:50 mark of this brief (3 min) video, there is a demo of interactive drawing and editing using the Cornu spline tool: http://www.youtube.com/watch?v=UX1HptFLObM

** Please note that this capability is a Ruby adaptation of path.py created by Raph Levien (http://www.levien.com) aided by insights from Cornu for Nodebox (nodebox.net/code/index.php/Cornu). Thanks to Raph and to the Nodebox team for their expertise, creativity and generosity. **

3. The capability to draw Euler spirals. This derives from the Cornu spline code because that logic is based on Euler spirals. I used this capability to design a part of this sculpture I recently completed:
   

Please let me know if you have any questions or problems.

Thanks again for the feedback on my ruby scripts.

Just FYI...

The Taper Maker script will draw tapered offsets in addition to tapered extrusions. You access this capability by entering one of the following in the options field on the input dialog:
"o" or "offset" or "offsets"

When this option is used, the script does not draw a tapered extrusion along your selected path. Instead, it draws four tapered offsets (paths) along your selected path. These paths would be centerlines along the faces of the tapered extrusion "above", "below", "left" and "right" of your path.

Here is an example of four tapered offsets around a path:
tapered offsets.pdf

This option facilitates using one tapered curve as the basis for another as in this metalworking example:
taper on taper.pdf

HTH

In response to a request for more information on how to use the (free) Curve Maker plugin to draw spirals, I prepared the attached tutorial. I welcome feedback on this tutorial.

Draw 2D Spirals Tutorial.skp

If you are not using the latest version (1.03), you will not be able to draw some of the Archimedean spirals in the tutorial that are illustrated in the attached pdf.

More information on the plugin is available at http://www.drawmetal.com/curvemaker and in this SketchUcation post http://www.sketchucation.com/forums/scf/viewtopic.php?f=180&t=10880

The plugin can be downloaded from http://www.drawmetal.com/download

Terry

Thanks to everyone for your positive feedback and encouragement. Please share images or links to interesting things you model with the plugins.

Thanks in particular to Daniel S for uncovering a bad bug that impacted users with a French, Spanish, German or Italian locale. I apologize to international users for not having been more sensitive to those pesky commas in positional notation and not fully appreciating what Ruby does and doesn't do.

In any event, I have posted updated versions that you can download from http://www.drawmetal.com/download. Alternatively, if you need more detailed installation instructions you can also download the plugins from http://www.drawmetal.com/installationinstructions.

Terry

Marcos -

Yes, that appears to be the issue. Thanks for helping diagnose the problem. Of course, it is not supposed to work that way. It appears to be a problem for people using PC's because I cannot replicate the problem on my Mac.

I have written some plugins targeted for architectural ironwork design which may also be useful in other contexts.

The first plugin draws curves typically seen in traditional metalwork (e.g. Bernoulli and Archimedean spirals and sine and cosine waves). In contrast to other curve drawing plugins, users input desired curve dimensions instead of parameter values for mathematical equations.

The second plugin draws tapered cross-sections (e.g. rectangle, square, hex, etc.) along an existing path.

The third plugin - of interest mostly to blacksmiths - calculates the amount of stock material required to forge a taper (and optionally the cost and weight).

These plugins and a user guide are available free of charge on my website http://www.drawmetal.com/.

Examples of metalwork fabricated from models that used the plugins can be seen at http://www.drawmetal.com/gallery.