Some performance questions on Desktop

[dana_swift]

Brady & Dave on "French Curves". Draftsmen used to keep a drawer full of greenish yellow curves, today all of them have been replaced with Bezier curves (or NURBS based on the same math.) Pierre Bezier was most definitely a frenchman! So today we still use French curves.. just different ones. Now they are just created graphically for each situation instead of having the old green ones that never quite fit the need.

Personally I will take modern Bezier curves over any plastic template any day. Especially because its easy to tell the Shopbot to follow a Bezier that was drawn in PartWorks, and very difficult to tell it to follow a piece of green plastic!

http://en.wikipedia.org/wiki/Bezier_curves
(Check out the animations at the bottom to see how they work, and how software converts the control points into tool motion!)

Most people never use the node editing mode in PartWorks to discover that many things are done with Bezier curves whether they knew it or not.

Cool stuff!

Oh- I still have a deci-trig-log-log K&E slide rule from when I started engineering school. I have my fathers also!

Sigh-

D

[JackM]

Dana... I have been lurking and researching my Boomer-Sooner butt off for a couple months now and I have to say, you are one of the more compelling characters on the forum boards. Partly because you are from T-Town but mostly because you have a Renaissance Man cachet. Your posts are always insightful and interesting. Hope to meet you and several other of the "usual suspects" from the SB forum.

[Brady Watson]

Dana,
I must be showing my age...I had a French curve in HS drafting class; two actually. One was that opaque snake vomit green color and the 'real nice' one was clear acrylic. I don't think either of them got very much use in drafting, but sure were fun for random doodling and strange geometric constructions

Thanks for the Wiki link - gonna check that out.

Most people never use the node editing mode in PartWorks to discover that many things are done with Bezier curves whether they knew it or not.

Absolutely. I am amazed at how many users never do any node editing. When I was first starting out, I would trace things out with arcs...and that never worked out as smoothly and perfectly as beziers do. I think it was watching James Booth @ an ArtCAM demonstration when I really 'got it' and now rarely use arcs for vector shape construction, unless that section of the part truly is an arc or arc section.

Mastering node editing is the key to all of these programs, especially if one plans on progressing to 3D. You must master 2D drawing before you can do any real work in 3D. Otherwise, even creating a good cross section for rail sweeps etc will be frustrating.

-B

[dana_swift]

Jack- thank you for the kind words. Meeting the shopbot community is one of the great things about having a shopbot. Go to the various shopbot events, you will be stunned at what people are making with their bots. Inspirational to say the least!

Brady- Bezier curves are fascinating. They are easy to explain to someone just wanting to draw a specific curve and not worry about the math behind. Yet most people never hear an explanation of what the 4 control points do and how to manipulate them to get exactly what is needed, so they seem confusing and remain unused. Tragic.

Hope you enjoyed the animations.

D

[bleeth]

As a marine carpenter/shipwright, learning early on about "fair" curves made working with beziers in software a natural. I still have my box of acrylic ships curves and do get them out for sketching. Many of the desks we build for our projects are curved but even when they are somewhat serpentine in shape the architect always draws the original design as a series of a few connected arcs and shoves the centerpoint around to achieve a close tangent instead of using beziers. This is probably due to making it easier to lay out for framing, etc., although from the state of so many of the architectural plans I see I wonder how they justify their fee and for the framers on many of my projects I will cut the shape out in some cheap mdf or garbage ply and screw it to the floor so they can plumb up from it.
Interesting sidenote: My automatic spellchecker tells me that bezier is not in its dictionary!!

[GDGeorge]

Dana,
I must be showing my age...I had a French curve in HS drafting class; two actually. One was that opaque snake vomit green color and the 'real nice' one was clear acrylic. I don't think either of them got very much use in drafting, but sure were fun for random doodling and strange geometric constructions
-B

So... If I take one of my old french curves and tape it to the work surface on my Desktop, I could set up the digitizer and...

Cheers,
J

[Tomlin]

Ok, so to bring this thread back on topic I first want to say "Thanks!" to all who gave such a great insight into the product.

I'm thinking that I read somewhere that although you can get the 2.25 hp router elsewhere for less money, that Shopbot actually modifies it for this machine?

[bleeth]

The router is not modifed, but the springs in the z, the mounting plate, and configuration in the controller as well as appropriate wiring and connectors is in their price. (You can buy a crate engine for less than a whole one properly installed)

[Tomlin]

Hi Dave

Thanks for the reply. Sorry, but what is a crate engine?

[hh_woodworking]

Crate engines are replacement engines purchased new and complete, shipped in wooden crates. Can be complete or missing existing fuel system,alternator, water pump or other accessories.