Circumference

 From: BurrMan 6 Apr 2009  (1 of 10)
 Hi MIchael, In another forum we're discussing unfolding a cone. In a tutorial I'm following I need to create an arc and control its length (the circumference length) I was trying to figure out if MoI does this and if so, Which input field it is. Otherwise, it becomes a math problem. The tute may be talking about a tool that MoI doesnt have yet. EDITED: 19 Jun 2012 by BURRMAN

 From: Michael Gibson 6 Apr 2009  (2 of 10)

 From: Michael Gibson 6 Apr 2009  (3 of 10)
 2558.3 In reply to 2558.1 Hi Burr, for the next v2 beta I've also added in a couple of helper functions for expressions to make it a bit shorter to do conversions from radians to degrees. So in the next beta you'll be able to enter in: deg( length/radius ) for this one. The new functions are deg() and rad() - deg() takes in a value in radians and converts it to degrees, and rad() takes in a value in degrees and converts to radians. - Michael

 From: BurrMan 6 Apr 2009  (4 of 10)
 2558.4 In reply to 2558.3 Thanks Michael! Could I see one short input line for reference? FYI: It's comming up for me with regard to programming 4th axis CNC work. Some of the lessor packages (under 5K) only do whats called "wrapping" which requires manual unfolding in certain aspects. This will help me alot! As you know, I am new to math so when you explain "radians" I have more homework! (57.2958!) I'v been looking at Lamina which is cool, but for some other specialized work. I very much appreciate your time in answering these things for me that really have nothing to do with the development of MoI. I'll always try to give back somehow. Burr

 From: Michael Gibson 6 Apr 2009  (5 of 10)
 2558.5 In reply to 2558.4 Hi Burr, no problem! Did that make sense for how to use that formula inside of MoI? Just in case here is a step-by-step for how to use it. Say you want to create an arc of radius 5.5 that has a length of 8.1 units. To begin with, start the Draw curve / Arc / Center command. Pick the center point somewhere that you want to place the arc at. For the start point of the arc, type in 5.5 to activate distance constraint. That will make the next point you pick be constrained to be 5.5 units away from that center point, that is how you set a specific radius value when drawing an arc with that particular arc tool. Then click to place that start arc point. Now the Arc command will be at the prompt that has an Angle: value you can enter. This is where you enter that forumla - to enter it press the Tab key to put keyboard focus into that Angle box (if you enter numerals your focus will go there automatically but since we are entering an expression that starts with a parenthesis character it won't go there automatically so hit tab to do it). Then you type in the formula: (8.1 * 180)/(5.5 * PI) So note there that I used this formula: (Length * 180) / (Radius * PI) but replaced the Length and Radius with the specific values for length and radius that you want to create for this arc. So those steps above will make an arc that has a length of 8.1 units. - Michael EDITED: 6 Apr 2009 by MICHAEL GIBSON

 From: Michael Gibson 6 Apr 2009  (6 of 10)
 2558.6 In reply to 2558.4 Hi Burr, > Could I see one short input line for reference? I think I wrote that last message before seeing this, but that one has step-by-step instructions, let me know if you get stuck on any step and I will show you an illustration for that one. - Michael

 From: BurrMan 6 Apr 2009  (7 of 10)
 2558.7 In reply to 2558.6 That was it and it looks like that is exactly what I need to do my "arc by length" thing. Thanks again.