Weird Measurement Anomoly
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I was working on a cabinet face frame and had a weird thing come up.I set my rails to guide lines a set distance apart ( 9 1/2") . When I measure from the top or bottom of the frame everything is as it should be.All the rails and spaces between equal the ht of the frame exactly. However, when I measure between the two spaces that should equal 9 1/2" one of them measures 9 9/16".I imediatly suspected one of the rails or other components to be off. I spent some time double checking and it's all good. I triple checked my math, all good. I only notised it when I put a verticle divider between and notised one to be 1/16" short.I fixed it by lengthening it but now my cutlist will be off on that one component. I can adjust for that, but now I have less faith in the program. Is this a known fault and if so how common is it?
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Otis
Yes this happens to me, either when I type in the exact measurement or use the tape tool. Te difference for me is that it is usually Archvis drawings, and are based on cad drawings where the measurements are accurate, so will not affect an outcome such as a cut list. So I let it go.
Strangely, the measurements are always 1/16" out. -
@otis said:
I can adjust for that, but now I have less faith in the program. Is this a known fault and if so how common is it?
sketchup is actually extremely accurate (within it's own allowances - 1/64" i think).. every time a post like this has come up (that i've seen), the error can be traced back to the user..
can you post a .skp showing the error? i'd be very(very) surprised to see a sketchup file showing what you're saying it is.
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This would be hard for me to do Jeff, as it usually involves an action that happens earlier on in the process,( i.e. typing in the parameters of the rectangle that will form the basis of the model, say 36', 24'), and then further down the line pulling of a measurement that indicates that it is 36' 1/16".
I usually type in my parameters, be it length of line, tape tool, or rectangle, so I'm sure I'm not adding 1/16". It has happened more than once, but as I said most of my clients wouldn't question the discrepancy, as it usually ends up as a visual, not a dimensioned drawing. -
i dunno, i use sketchup for working drawings all the time.. often way more complex than boxy type construction.. i've never once found a mathematical error by sketchup itself and if i did come across a discrepancy, i could trace it back to myself and/or my drawing method..
my post was more directed at otis though who is seemingly saying that in his .skp file, 1 + 1 = 3.
here's a thread from a while back where the user was saying something similar.. maybe something like this is happening to otis?
http://forums.sketchucation.com/viewtopic.php?f=15&t=23381 -
Well there is no doubt that during the process I could have done something that bumped the measurement, the same way I sometimes inadvertently erase something in an cleanup. I will be paying more attention.
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First thing might be to check to make sure the Units Precision is set to the most precise. If it isn't, the dimensions can be rounded off.
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Interesting, although my precision was set to 1/64, snapping was at 1/16, so that may have been my problem. That's why these threads are so valuable. Thanks
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I knew it had to be me, or is it. Here's the frame in question. Somehow it don't work out right, I think.
Notice the one opening at 9 9/16" when measured directly, then add up the measuremnts taken from the top down, or visa versa.I work to 1/64" BTW.
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otis..
didn't realize you were using the dimension tool as a means of measuring.. using that won't include the '~' in front of the dimensions.
if you measure your distances with the line tool or the tape measure , then you'll see that your distances are written like " ~9 9/16" .. (notice the ~ symbol in front of the numbers.. that means approximately)
the accuracy in the file is set to 1/16" so sketchup will only go down to 16ths.. if the real dimension is say 5/64 then sketchup will display ~1/16" which is the closest 16th to 5/64.
you can change the accuracy in model info -> units but even then, this file still has the '~' symbol showing up in front of some of the measurements.. (meaning some of your rails are placed at 128ths" or smaller)
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Dang, you're right. I always work to 1/64, so I didn't even check to see that somehow the units got changed. My bad
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here's a version drawn to the specs i think you're after.. (also cleaned up some weird things in there... hidden vs. softened lines.. if those were intentionally hidden instead of soft, sorry)
the left/right measurements were a little screwy as well but it's now exactly 31 x 48
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Thanks Jeff, that looks good. I know I've had a brain fart when I look at my spelling.
A-N-O-M-A-L-Y. There , I knew I could do it 
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Hi folks.
Make sure that you disable length snapping in Model infos --> Units. It may create unwanted snaps on an invisible grid that may not match your intended intervals.
Since SU can accept precise values and its inference engine is also precise, I don't use this feature.
Just ideas.
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