FreeCAD - Gorgeous! I am a little intimidated!

[devils4ever]

I regularly enter dimensions in equation form without brackets. For instance, I can enter: 0.375/2" and it converts to 0.1875".

What I don't like, is when I enter: 13" and it displays it as 1.08333' and 0.099" becomes 99 thou.

It seems to use the nearest unit.

 

[graham-xrf]

I regularly enter dimensions in equation form without brackets. For instance, I can enter: 0.375/2" and it converts to 0.1875".

What I don't like, is when I enter: 13" and it displays it as 1.08333' and 0.099" becomes 99 thou.

It seems to use the nearest unit.

Yep - I can see why that grind on you a bit!

Of course - it's not wrong in the calculation, but is apparently contrary in adopting "thou" just because it saw a small value inch, and at the same time heads for feet as the default unit.

This is just a thought, but in Edit --> Preferences --> Units, there are four non-metric choices, and especially, a box to choose "Minimum fractional inch", which comes alive when units selected are..
Selection --> "Building US (ft-in/sqft/cft"
The fractional can be anything from 1/2" all the way to 1/128", with default at 1/8".
It might be that if your number has a fractional part smaller than 1/8", it will change to thou.

Maybe try one of the others, likely the first. The list is ..
1. US customary (in/lb)
2. Imperial decimal (in/lb)
3. Building US (ft-in/sqf/cft)
4 Imperial for Civil Eng (ft, ft/sec)

Regarding dimensions in equation form without brackets, I first get curious about which FreeCAD version are you using, and which OS?

I encountered FreeCAD some while ago, before it became what it is now, and it did exactly as you describe - but not any more. For dimension entry, my FreeCAD 0.19 on a Linux box does not respond to pressing / unless I surround the expression with normal brackets.

Curiously, it does accept the + and - operators, so addition and subtraction inline arithmetic seems OK - no brackets needed. It may be a bug, or perhaps a situation to stay seamless without breaking when moving between separated bodies.

So now you got me checking. In both US customary (in/lb), and Std metric, it allows + and - and * , but not /.
This is something I will put to the FC forum.

My main use for inline arithmetic was to enter a diameter/2 to get a radius. Now, the circular dimensioning tool has the options to enter diameter or radius as you might prefer.

I understand there are compelling mathematical reasons for FreeCAD to ultimately compute from radius within.

[EDIT: OK - this thing is now known from six days ago, and there are guys going after fixing it. (Ticket #4422)
The parsing of "/" in a line where the user may even have typed various other stuff after / is not easy!
The fix must not break any of the other workbenches, and has to be consistent throughout.
END EDIT]

 

[devils4ever]

I tried changing the preferences, but it did nothing. Same as before.

I'm running FreeCAD 0.18 on Windows 10.

 

[graham-xrf]

I tried changing the preferences, but it did nothing. Same as before.

I'm running FreeCAD 0.18 on Windows 10.

OK - I suppose the first thing to do is try out version 0.19.
I think they can be run alongside each other.

Everything else about W10 is alien to me, but I think what FreeCAD does is identical in Windows as in any other plaform.

 

[ghack]

Nope, you can use imperial! There is a global setting in the preferences that selects between a few different options. This might be a little outdated(as far as the options), but shows how:

Or is that it will only post in metric? one the packages i was looking at that was the case. Which is no good either cause then i would have to change my machine parameters and i wont do that.

 

[ErichKeane]

Or is that it will only post in metric? one the packages i was looking at that was the case. Which is no good either cause then i would have to change my machine parameters and i wont do that.

I don't know anything about 'post', I'm a manual guy so the only thing I do after modeling is to get a drawing *shrug*.

 

[graham-xrf]

Or is that it will only post in metric? one the packages i was looking at that was the case. Which is no good either cause then i would have to change my machine parameters and i wont do that.

You can have FreeCAD set to work completely, consistently, and universally in imperial units.
If you happen to inadvertently type in a dimension that is smaller than appropriate for the number of decimals you chose as a display preference, it may temporarily offer "thous", but will still accept if you use " or inch, or in, instead.

If you change the universal preference to another unit after or during the sketches being made, all are converted if you reload the model. Of course, they can all convert back just as easily.

If the number you type in is too close to the sizing implied by the of decimals you choose to have displayed, the entry will offer "thous". You can either go with it, or ignore it, and type in ", or "inch", or "in", instead, backing out the "thous". (Allow here that it is awkward to put a inch " " " character in quotes ).

Internally, the calculations are done to the full precision. Dimensions are not internally mathematically rounded for the number of decimals you choose to show. The displayed decimals are (rounded).

 

[ghack]

Ok like i said there was one i was trying and even though you could draw in inches it would only post in metric which is useless. And i only cad for use on my cnc mill.

 

[graham-xrf]

Ok like i said there was one i was trying and even though you could draw in inches it would only post in metric which is useless. And i only cad for use on my cnc mill.

When you say "post", I am not sure what you mean?
For the way I use it, I may not have ever tried the same thing you have, so this could be something just waiting to trip me up when I do encounter it.

I am guessing that you want to export a file to use to control a CNC machine.
I expect that there are likely a great many who do already exactly that - and in inches too!
We just have to figure out what exactly is the end thing you want it to do.

 

[ghack]

yes, tool path the part and then post process which generates the g-code for specific machines. like for a milltronics or hass ect.