Always round up or down dimensions.

[knobhead]

I've got an annoying problem with dimensioning. I'm working for a customer drawing in metric units, and my company still works in imperial (english). Now, I'm converting dimension values as I go, but when it comes to tolerancing my drawing, I have to edit each dimension individually. The reason is, I have to be sure that the imperial values I use fall within the tolerance limits on the metric drawing. For example, a top limit of 147.31mm converts to 5.7996. If I'm working to three decimal places, autocad will round that off to 5.800, which will potentially put me out of tolerance by 0.0004, or 0.01mm. Not much, granted, but it is out of tolerance. I have to manually check and change every dimension, top and bottom limits, to make sure it is within the metric limits!
Right, so is there a way to force acad to always force a top limit tolernace to round down, (making the above example 5.799), and bottom limit tolernace to always round up? I will be definitly always be within limits then, and it will let me use the dimensioning system of autocad the way it's supposed to be used, rather than having to do all my dims manually. It takes ages, and is boring.

 

[shadow]

this may or may not work but its worth a shot
do you know the variable dimrnd set it to .0001 but in your dimension style set your primary units precision to 3 places after the decimal this i think would indicate to autocad that you want to round to 4 places but only want to show 3 does that sound right if everyone helps everybody the world will be a better place

 

[knobhead]

Thanks, nice try, but no cigar. That's not quite what I want to do! The problem is if the last digit of my converted value is 5 or above, the dimension I use will be rounded up, and down if it's below. Perfectly normal and reasonable, but often the value I end up at, when converted back to metric units, is outside the tolerance the customer demands. So what I want to do is have the resulting dimension rounded down for the top limit tolerance, and up for the bottom limit tolerance, no matter what the last digit is.
For example, say I'm working to 1 decimal place, and say my converted figure for the top limit of my dimension came out at precisely 1.46, and anymore than that is out of limits. For the top limit I'd use on my drawing, I'd want the dimension to say 1.4, even though the rounded value should be 1.5, to ensure I stay in tolerance. (Remember, any more than 1.46 and I go too big.) Conversely if I had a value 1.44 for the bottom limit, I'd want dimension to say 1.5, even though the rounded value should be 1.4 (any less than 1.44 and I go too small.)
It sounds complicated as heck written down!



Going to a greater number of decimal places reduces the error, obviously, but there is still an error, and I'm working to plus/minus 0.0001". Small errors are still big!

 

[shadow]

Sounds like something that might be more easily accomplished with auto lisp but i have know idea how i guess you would have to come up with a set of rules for your specific needs if everyone helps everybody the world will be a better place

 

[knobhead]

Um, I'm using Acad LT too, so that won't work either! Thanks for the suggestions though, I think it's time to fill in a wish list form at autodesk.

btw, since when was h e ll an offensive word? My last post edited it to heck. And even if you do consider it offensive, how the hel, er heck, do you survive in engineering? There's a foreman here who can, and does, swear for 20 mins without repeating himself.
Usually at me.