@ellipser said:

I'd like to learn how to interface C++ with Sketchup, so I can speed things up. Basically my problem is that I need a road-map of sorts to get there.
First thing is, what C++ compiler should I use? Visual Studio? I don't want to pay Bill Gates $500 for just hobbyist work that I'm doing. I used DevC++ before. I'm not at all familiar with Xcode, so I guess I'll Google that after I'm done writing this post.

https://github.com/SketchUp/ruby-c-extension-examples
That git repo includes Visual Studio and Xcode project examples for an Hello World extension - including the Ruby libs and headers we use.

@ellipser said:

I've seen the SDK code on the Trimble site, but, what next? Step 1 would be of course to download a C++ compiler. Then what? Where do I put all the header files? Could you recommend a tutorial if there is one?

The C SDK is for reading and writing SKP files -not for acting on the live model.

@ellipser said:

Ultimately, I'm going to interface Sketchup with my 3D printer, which is in the final stages of being made. (It already does plotting when provided G-code). Next step is mounting the extrusion head and generating G-code from a Sketchup file. Also, with just using the Dremel mount I have, I can do milling. I want to do some Celtic designs created in Sketchup and then milled into wood.

Nice! Got a project blog?

For people just getting started with plug-ins, here's how you use one:

Download the plug-in attached to the thread's first post.

Click/drag it onto your desktop.

Open any folder, and go look for where Sketchup's plugin file is kept on your computer. On mine it's in C:\Program Files (x86)\SketchUp\SketchUp 2013\Plugins
This is also called a "path" in computer lingo.

Your path should be something similar. This is where you get to add features to your copy of Sketchup.

Drop the Spirograph.rb file from step 2 into that folder. You have to re-start Sketchup to use it, because Sketchup only loads plugins at start-up.

You should see a Plugin called "Spirograph". Try some settings like:

16
8
7
20

and have fun.

You can easily crash your system if you over-burden it with too many segments. Every curve can be reduced to line-segments, and "segments" is the setting you change to get a smoother effect. Too much smoothing will result in a system crash. It's sort of like that sandbox tool. It doesn't take too much to crash the system if you have an average-speed computer like mine. (For you pros using a graphics card of something, that probably doesn't apply.)

20 is a good number for reasonable smoothness for segments.

Anything above about 30 for the fixed radius is a bit much too. You don't end up with a nice design anyway, but a dense mat of lines/edges.

At some point it may be possible to use some C++ code to do the heavy multiplications internally done in the plugin to reduce crashes, but for now, I'm using the convenience of Ruby at the expense of system resources.

Pretty cool, huh? Takes you back to when you were a wee-lad and using those sharp-pins that held down the fixed radius. They wouldn't allow any sharp edges in any toy today, now would they?

See also

https://sites.google.com/site/sketchuptogcode/

http://sketchucation.com/forums/viewtopic.php?t=49346

http://sketchucation.com/forums/viewtopic.php?f=323%26amp;t=45496

Phlatforum on the cutting edge of RC

http://cncutil.org/