Circle Tool ... specify diameter
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@jclements said:
For the mathematically challenged, a way to enter a diameter rather than a radius. Maybe toggle between radius or diameter entries using the Tab Key or simply following any numeral in the VCB with a "d" or an "r".
Pull out a circle, in the VCB type 1000/2 and you get a circle of radius 500, calculated from the diameter 1000 - so it's already there...
When making a circle typing into the VCB a number on it's own [500] sets the radius, a number followed by /2 [1000/2] sets the radius [500] from the diameter.. and also a number followed by an S changes the number of edges (segments) the circle has [32s = 32 segments] - the more it has the finer it is an appears graphically BUT the more facets it makes when it's made 3D... Since most cylinders etc made from circles as 'smoothed' they can have relatively few edges BUT still look OK whilst keeping the poly count down...
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John, the / operator does indeed work. Maybe I'm just lucky living in the metric world so by default I only have one unit to play with thus I don't need to type the foot sign.
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G,
Maybe it would be easier to move to Europe. :}
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I realize you can use the / operator as you suggest. However, if I input the Unit of measure in the VCB, ie., 6'/2 , I get a radius of 6'. Also, I don't believe you can input fractions either with the / operator. Am I entering info into the VCB using the wrong syntax?
I often am given xerox copies of old hand-drawn drawings or sketches to reproduce which have dimensions such as 6 5/16" Diameter. Is there a convenient way to enter this info using the Circle Tool in SU .... If not, then perhaps my original request would be useful.
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Actually if the only obstacle that does not let you use this option is that you need to enter the footage/inchage, there must be a solution for this (after all SU is developed in the States...)
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I see that as a need too. I think even metric users would have the same problem. If I want a circle with a diameter of 4.5mm, entering 4.5/2 gives me a diameter of 9.
You are right that there isn't a good way to enter a circle with a diameter of 6 5/16". Usually, in my head I can convert it to a simple fraction of (6*16)+5/16 = 101/16 for the diameter then double the bottom number to get the radius = 101/32.
Actually if it's gotta be right and I have to do (6*16)+5 in my head, I pull up the calculator real quick to make sure I'm not screwing something up. Some combination of poor math skills and poor self confidence I guess. Regardless it's one way of accomplishing your goal.
Being able to enter mathematical equations in the VCB would be a better solution and I hope that makes it to future versions.
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Now this is true with the decimal fractions - I've just tried (though I can imagine TIG coming up with an explanation and method about it).
Of course, as a workaround, we can always scale a circle to a specific size and the scale tool will work with its diameter but I know workarounds are just workarounds...
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G,
I think scaling is the best/quickest "workaround".
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6+5/16 ?
what number is that? 11/16" ?
6 5/16" -
Using decimal numbers /2 works fine... but with fractional inches it's useless... BUT the trick in halving fractional inches is the halve the whole inch part and double the fractional divisor...so...
6 5/16"
when /2 becomes
3 5/32"
It works for any combo...
BUT for 'odd' inches you do need also to add a 1/2" to the fraction, by adding the original fractional divisor !
11 7/8"
when /2 becomes
5 **8+**7/16" >> 5 15/16[/b]"
where the 1/2" is rendered as 8/16" - the 8 being the original divisor that is simply added to the top number [here 7 giving 15]...
So if you insist on using fractional inches then you need to learn some simple math tricks to halve dimensions...
Don't start going down halving fraction feet-and-inches !
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Decimal inches are handy. You can change back when doing standard dimensioning.
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@tig said:
So if you insist on using fractional inches then you need to learn some simple math tricks to halve dimensions...
right... though people that use fractional inches a lot generally have all that stuff ingrained in memory without needing to calculate (in the same way you know 7*8=56 without actually calculating it)
(well.. i guess we generally only have the 16ths and less ingrained.. if i start getting into 32nds and 64ths then i have to stop and think about it)..
but for me, the math trick for half of 11 7/8 would be 12/2 then subtract 1/16.. probably a lot of ways to arrive at the same answer but that's generally the way i do it on the fly..
regardless.. i think entering (11 7/8)/2 or even 11 7/8 ÷ 2 would be a lot less confusing than putting a + in the mix
[late Edit-] ah.. i see where you're putting the plus sign now.. the same place as in the example i used except i'd be putting a minus instead (11 16-1/16).. (11 & 16/16 -1/16).. not sure if id ever enter like that in the vcb but at least i see what you're talking about now
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Personally, I think all the math workaround suggestions miss the point: computers are supposed to do the math for us so we don't have to bother with it. It is a bit ridiculous that a sophisticated program running on an expensive computer can't even do all the simple math functions of a $10 pocket calculator, much less provide a user-friendly way to accept fractional or mixed unit expressions!
This isn't rocket science. Writing the code to parse an unambiguous arithmetic expression like (2' + 4mm)/2 is something any competent programmer should be able to do without breaking a sweat. Likewise, it is not much of a challenge to write the code to recognize a trailing "d" as a diameter specifier.
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Do not get into the habit of using /2, since SU has a significant bug: appending /2 works SOMETIMES -but only if you are dividing an integer by 2. If you type "1.5/2" you will not get a .75 radius as you expected. There is no warning in SU v.8; in fact this bug has not been fixed as of the 2014 version.
It would not be hard to parse the input line, then one could enter 6+5/16 for the mixed fraction since that's what we really mean for 6 5/16. (As we learned in 7th grade algebra, multiplication and division are always done before addition and subtraction -MDAS "My Dear Aunt Sally" rule).
It would be nice to be able to specify relative/absolute references, and variables too.
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