[kicad-users] Re: Feature request: Hard metric
--- In kicad-users@yahoogroups.com, Brian Sidebotham brian.sidebot...@... wrote: 2009/7/8 einazaki668 einazaki...@...: In the PCB tool (and module editor) I think it'd be a good idea to use hard metric when in metric mode, rather than the metrified english as it's now done. TIA, eric The trouble is, that the units have to be something internally in the software. mils is best for this. At the moment there isn't enough rounding of metric though imo. So for the majority of the time you have to interpret 69.999 or 69.998 as 70mm. I think if the units displayed were rounded to the nearest 0.01mm (~1/2 thou.) this would make work in metric much easier. Best Regards, Brian. It's not just that. When in metric mode the grid spacing is still based on inches just multiplied by 25.4. So if I'm building a module based on a vendor's drawing and the vendor is using hard metric it's a big pain because I can't use grid snapping. The user defined spacing, I find, is really not much help. eric
[kicad-users] Re: Feature request: Hard metric
--- In kicad-users@yahoogroups.com, al davis a...@... wrote: On Thursday 09 July 2009, Robert wrote: America is the last country in the world where engineers prefer to use them. American engineers don't prefer traditional units. It's the non-engineers. When speaking of inches you have to distinguish between decimal inches (mils) and fractional inches as well as feet and inches vs inches only. If you work strictly decimal inches it's no better or worse than metric, IMO. eric
[kicad-users] Re: Feature request: Hard metric
--- In kicad-users@yahoogroups.com, einazaki668 einazaki...@... wrote: In the PCB tool (and module editor) I think it'd be a good idea to use hard metric when in metric mode, rather than the metrified english as it's now done. TIA, eric Well, I am a dope. There is a hard metric grid after all. It's towards the bottom of the pull-down. There are also inchified metric grids in inch mode. As Brian(?) mentioned, it needs to be rounded off better. eric
Re: [kicad-users] Re: Feature request: Hard metric
I would agree if it wasn't for the fact that everything else in the engineering world is specified in metric, and PCB's don't live in a bubble isolated from that metric world. Now that electronic components are (finally) going metric, having PCB software that doesn't work well in metric is becoming more and more of a problem. Since kicad is currently based on traditional units, could the problem of rounding be solved by allowing the user to specify what the base units represent (and then storing that specification in the file so kicad always knows what base units it should be using)? Regards, Robert. When speaking of inches you have to distinguish between decimal inches (mils) and fractional inches as well as feet and inches vs inches only. If you work strictly decimal inches it's no better or worse than metric, IMO. eric Please read the Kicad FAQ in the group files section before posting your question. Please post your bug reports here. They will be picked up by the creator of Kicad. Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library. For building Kicad from source and other development questions visit the kicad-devel group at http://groups.yahoo.com/group/kicad-develYahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.387 / Virus Database: 270.13.8/2227 - Release Date: 07/09/09 05:55:00 No virus found in this outgoing message. Checked by AVG - www.avg.com Version: 8.5.387 / Virus Database: 270.13.8/2227 - Release Date: 07/09/09 05:55:00
[kicad-users] Re: Feature request: Hard metric
Not true. I'm an American engineer, and I prefer English units for certain applications (and metric for others). 1) The proper name is English units. It has nothing to do with the present practices of England, the country; that's where they originated from, so that's what they're called. They're not Roman units (how ridiculous), because the Romans didn't have inches. This is just like how the English language is called English, even though the way it's spoken in places like the USA and India is very, very different from the way it's spoken in England presently. 2) English units are more convenient for some things, such as temperature (when relating to humans, like for setting your thermostat, not when doing calculations in a lab). The Fahrenheit scale is better scaled for the human range of temperature, and doesn't require messing with fractional units the way Celcius does. The Fahrenheit thermostats in our homes are in whole degrees only, because a half-degree of precision is pointless in Fahrenheit since humans can't really tell the difference. But half-degrees in Celcius thermostats are necessary because humans certainly can tell the difference there (being about equivalent to a whole Fahrenheit degree). 3) It's funny how UK residents like to claim they don't use English units any more, when in fact they do: the talk about speed in miles per hour, and they order beer in pints, and they relate their body weight in stones (whatever those are), not kilos. This isn't much different than the USA, where people's speedometers are in MPH, their weight in pounds, etc., but when they go into a science lab, everything is in metric. Metric proponents talk about how useful it is to be able to convert between units so easily with metric, like converting kilos and meters to Newtons or whatever, but what they're missing is that most people don't do this! No one is going to step on the scale, read their weight, and then need to convert that into a torque or force. No one wants to read their home temperature on their thermostat and then calculate thermal energy. There's a big difference between what regular people do in their daily lives, and what scientists and engineers do for work. That's why even here in the USA, most scientists and engineers (esp. scientists) work with metric units at work, and then go home and set their thermostat in Fahrenheit and read their weight in pounds, and don't have a big problem with this discrepancy. 4) Inches (or more importantly, mils) are still pretty useful in PCB design. It's easy to remember things like 8 mil minimum track width, 20 mil track-to-board-edge spacing, etc. Also, many many components are designed in mils: most chips have pin spacing in mils: 100 mils for DIP chips, 50 mils for SOIC, 25 mils for TQFP, etc. However, more and more components are showing up in metric, and that is annoying with Kicad since it doesn't have hard metric; instead of .1mm spacing, I have to choose .1056644353 or whatever. This really needs to be fixed; I should be able to lay out a PCB with both English and metric components without so much slop on the metric ones. Why does Kicad even have this soft-metric thing? If I want English, I'll select English. If I select mm, that means I'm working with a part designed in metric, and I need metric. Dan --- In kicad-users@yahoogroups.com, al davis a...@... wrote: On Thursday 09 July 2009, Robert wrote: America is the last country in the world where engineers prefer to use them. American engineers don't prefer traditional units. It's the non-engineers.
Re: [kicad-users] Re: Feature request: Hard metric
Actually, the correct terminology is Imperial units, not English. And mils is actually a unit of angle. the correct terminology for 1/1000 of an inch is thousandth or thou. On Thu, Jul 9, 2009 at 1:30 PM, Dan dan...@wolstenholme.net wrote: Not true. I'm an American engineer, and I prefer English units for certain applications (and metric for others). 1) The proper name is English units. It has nothing to do with the present practices of England, the country; that's where they originated from, so that's what they're called. They're not Roman units (how ridiculous), because the Romans didn't have inches. This is just like how the English language is called English, even though the way it's spoken in places like the USA and India is very, very different from the way it's spoken in England presently. 2) English units are more convenient for some things, such as temperature (when relating to humans, like for setting your thermostat, not when doing calculations in a lab). The Fahrenheit scale is better scaled for the human range of temperature, and doesn't require messing with fractional units the way Celcius does. The Fahrenheit thermostats in our homes are in whole degrees only, because a half-degree of precision is pointless in Fahrenheit since humans can't really tell the difference. But half-degrees in Celcius thermostats are necessary because humans certainly can tell the difference there (being about equivalent to a whole Fahrenheit degree). 3) It's funny how UK residents like to claim they don't use English units any more, when in fact they do: the talk about speed in miles per hour, and they order beer in pints, and they relate their body weight in stones (whatever those are), not kilos. This isn't much different than the USA, where people's speedometers are in MPH, their weight in pounds, etc., but when they go into a science lab, everything is in metric. Metric proponents talk about how useful it is to be able to convert between units so easily with metric, like converting kilos and meters to Newtons or whatever, but what they're missing is that most people don't do this! No one is going to step on the scale, read their weight, and then need to convert that into a torque or force. No one wants to read their home temperature on their thermostat and then calculate thermal energy. There's a big difference between what regular people do in their daily lives, and what scientists and engineers do for work. That's why even here in the USA, most scientists and engineers (esp. scientists) work with metric units at work, and then go home and set their thermostat in Fahrenheit and read their weight in pounds, and don't have a big problem with this discrepancy. 4) Inches (or more importantly, mils) are still pretty useful in PCB design. It's easy to remember things like 8 mil minimum track width, 20 mil track-to-board-edge spacing, etc. Also, many many components are designed in mils: most chips have pin spacing in mils: 100 mils for DIP chips, 50 mils for SOIC, 25 mils for TQFP, etc. However, more and more components are showing up in metric, and that is annoying with Kicad since it doesn't have hard metric; instead of .1mm spacing, I have to choose .1056644353 or whatever. This really needs to be fixed; I should be able to lay out a PCB with both English and metric components without so much slop on the metric ones. Why does Kicad even have this soft-metric thing? If I want English, I'll select English. If I select mm, that means I'm working with a part designed in metric, and I need metric. Dan --- In kicad-users@yahoogroups.com kicad-users%40yahoogroups.com, al davis a...@... wrote: On Thursday 09 July 2009, Robert wrote: America is the last country in the world where engineers prefer to use them. American engineers don't prefer traditional units. It's the non-engineers. -- IBA #15631
Re: [kicad-users] Re: Feature request: Hard metric
Many people here would refer to English units as Imperial measurements. They also go back much further than the Empire... They are a very natural unit for people to work in, which is why they are still used. Pounds, ounces, yards (an arms length)., miles, stones, feet (on the end of your leg), inches and all the normal stuff. In fact there has been a lot of arguments relating to some stores selling goods in pounds and ounces rather than kilos. totally stupid, as it makes no difference and if it helps som old lady only used to Imperial, then that's fine bu me. A colleague of mine once described things like pounds and stones as a comfortable sized rock that you could throw at someone on the battlefield, (pound) and a stone was the size of a big stone that you could repeatably lift and drop over the battlements onto the invading force. I don't know if that description has any truth in it, but it sort of sounds plausible and gives a good idea as to the natural description I used. A stone is 14 pounds. Body weight in stones is much easier for us to visualise than when stated in pounds. we are simply used to doing things that way. Myself, I've been using Metric most of my life and there is no problem swapping between the systems, so all the fuss is generally due to the politics here more than anything else. In KiCad there must be a way to use both, and more importantly you must be able to use both at the same time. In the PCB layout I don't think there is a problem, as the tracks will snap to the pads and such like, however I'm fairly sure that there is a problem with eeschema in that if the lib grid is different to the current working grid then connections may not be made. I don't think that there is the equ. of a magnetic pad effect. so one way or another that needs some work done on it. Andy On Thu, 09 Jul 2009 17:30:34 - Dan dan...@wolstenholme.net wrote: Not true. I'm an American engineer, and I prefer English units for certain applications (and metric for others). 1) The proper name is English units. It has nothing to do with the present practices of England, the country; that's where they originated from, so that's what they're called. They're not Roman units (how ridiculous), because the Romans didn't have inches. This is just like how the English language is called English, even though the way it's spoken in places like the USA and India is very, very different from the way it's spoken in England presently. 2) English units are more convenient for some things, such as temperature (when relating to humans, like for setting your thermostat, not when doing calculations in a lab). The Fahrenheit scale is better scaled for the human range of temperature, and doesn't require messing with fractional units the way Celcius does. The Fahrenheit thermostats in our homes are in whole degrees only, because a half-degree of precision is pointless in Fahrenheit since humans can't really tell the difference. But half-degrees in Celcius thermostats are necessary because humans certainly can tell the difference there (being about equivalent to a whole Fahrenheit degree). 3) It's funny how UK residents like to claim they don't use English units any more, when in fact they do: the talk about speed in miles per hour, and they order beer in pints, and they relate their body weight in stones (whatever those are), not kilos. This isn't much different than the USA, where people's speedometers are in MPH, their weight in pounds, etc., but when they go into a science lab, everything is in metric. Metric proponents talk about how useful it is to be able to convert between units so easily with metric, like converting kilos and meters to Newtons or whatever, but what they're missing is that most people don't do this! No one is going to step on the scale, read their weight, and then need to convert that into a torque or force. No one wants to read their home temperature on their thermostat and then calculate thermal energy. There's a big difference between what regular people do in their daily lives, and what scientists and engineers do for work. That's why even here in the USA, most scientists and engineers (esp. scientists) work with metric units at work, and then go home and set their thermostat in Fahrenheit and read their weight in pounds, and don't have a big problem with this discrepancy. 4) Inches (or more importantly, mils) are still pretty useful in PCB design. It's easy to remember things like 8 mil minimum track width, 20 mil track-to-board-edge spacing, etc. Also, many many components are designed in mils: most chips have pin spacing in mils: 100 mils for DIP chips, 50 mils for SOIC, 25 mils for TQFP, etc. However, more and more components are showing up in metric, and that is annoying with Kicad since it doesn't have hard metric; instead of .1mm spacing, I have to choose .1056644353 or
Re: [kicad-users] Re: Feature request: Hard metric
Dan wrote: 1) The proper name is English units. It has nothing to do with the present practices of England, the country; that's where they originated from, so that's what they're called. They're not Roman units (how ridiculous), because the Romans didn't have inches. This is just like how the English language is called English, even though the way it's spoken in places like the USA and India is very, very different from the way it's spoken in England presently. In the UK, the units Dan is talking about are properly known as 'Imperial' units... While nearly all countries have some customary units, in most cases (including, I understand the US) these are related by local law to the internationally agreed SI units. I'm quite fond of my (Imperial) pint (568ml) and some of my Swedish friends still think informally in term of 'thumbs' (1 thumb ~ 25mm) and Swedish miles: ~10km IIRC. Incidentally, the Romans did have inches. Known as 'unica' in Latin, they equated quite closely to the 'imperial' inch at about 24.5mm. What _is_ different about the US is that quite a lot of engineering is still done in customary units which have become obsolescent in the rest of the world. Best wishes Chris Bartram in Wales/ yn Nghymru - not in England!
[kicad-users] Re: Feature request: Hard metric
No, the correct terminology for 1/1000 of an inch is mil. There's countless PCB manufacturers who agree with me on this, so I'll take their word on it. Here's what Wikipedia has to say about it: http://en.wikipedia.org/wiki/Thou_(length) According to this, mil is the older term, and was only replaced in some places by thou when the SI system came about, because of possible confusion with millimeters. But mil is still in widespread use. From the article: In the United States, the mil/thou is still in use extensively in certain industries such as in the manufacture of printed circuit boards (PCBs) and for tolerance specifications on hydraulic cylinders. Apparently, the PCB industry hasn't adopted thou, since every time I look at some Chinese PCB maker's website, they use mils. Dan --- In kicad-users@yahoogroups.com, Chris fj1...@... wrote: Actually, the correct terminology is Imperial units, not English. And mils is actually a unit of angle. the correct terminology for 1/1000 of an inch is thousandth or thou.
Re: [kicad-users] Re: Feature request: Hard metric
You hit the nail on the head 'In the United States'... I have always used thousandth or thou, and I grew up in England. where the dimension was probably first used. However, it's kind of ironic, that in the US, the prefix 'mil' is used, since the _preferred_ SI units are all magnitudes of three... and hence why milli is used more often than deci or centi. Chris On Thu, Jul 9, 2009 at 7:14 PM, Dan dan...@wolstenholme.net wrote: No, the correct terminology for 1/1000 of an inch is mil. There's countless PCB manufacturers who agree with me on this, so I'll take their word on it. Here's what Wikipedia has to say about it: http://en.wikipedia.org/wiki/Thou_(length) According to this, mil is the older term, and was only replaced in some places by thou when the SI system came about, because of possible confusion with millimeters. But mil is still in widespread use. From the article: In the United States, the mil/thou is still in use extensively in certain industries such as in the manufacture of printed circuit boards (PCBs) and for tolerance specifications on hydraulic cylinders. Apparently, the PCB industry hasn't adopted thou, since every time I look at some Chinese PCB maker's website, they use mils. Dan --- In kicad-users@yahoogroups.com kicad-users%40yahoogroups.com, Chris fj1...@... wrote: Actually, the correct terminology is Imperial units, not English. And mils is actually a unit of angle. the correct terminology for 1/1000 of an inch is thousandth or thou. -- IBA #15631
