cath — 2017-05-14T06:40:05-04:00 — #1
Hello everybody !
I use PM pro and MG.
I have a little problem which I cannot solve.
As part of my sewing training, I have created a macro for a sloper.
As the training requires to work with a mini mannequin (40 european size/2), the measurements are very accurate.
For example, the bust total size is 48.5 centimeters, and the front bust half size is 13.13 cms.
I have drafted in MG with those measurements, and it appears as applied in PM when I check with the dimension tool.
But when I print, the bust front half size becomes 13.00 cms on the paper !
It is the same for the bust back half size, it becomes 12.00 instead of 12.13.
I print of course without changing the scale or adapting to the printer.
I have tried to generate a pdf file, that's the same.
That's really annoying, I cannot use the software if the printed pattern is not exactly correct, and most of all, if I cannot be sure it will be correct each time I draft and transform !
Does anybody have an idea ?
stofftante — 2017-05-14T15:50:47-04:00 — #2
Maybe it happens because of the conversion cm calculated into inches. ( By the way: It is not good in my opinion. But it is an american program). And the printer maybe acts like this too. The factor in PM is 2.54 - this is precise enough for a normal draft. The second decimal number is within the limits of the error calculation (do not know the exact english technical term) and so it is when you have 12.13. The 0. 3 mm you can not draw with a pencil - but the 1 mm should be there. Maybe you can try to scale with PM . If the conversion is the case there must be a logic behind this.
cath — 2017-05-15T04:35:47-04:00 — #3
Thank you for your quick reply !
I look at this and I post the result.
Have a nice day !
cath — 2017-05-16T04:54:54-04:00 — #4
I think you are right.
I have checked each mesurement on the printed draft, and each measure with 2 decimals after the point, has been automatically rounded down to the nearest number with one decimal place.
Specifically, the bust front and back measurements have been rounded down to the nearest whole number, I think this is beacuse other rounded down measurements had already been used, and it had to fit. Thus I have lost 0.26 cms for a half bodice, 0.52 cms for the whole bodice and it doesn't fit as it is a sloper without ease at all.
Well, I am really in trouble if I have to round up each measurement in order to anticipate what the software will do ...
eugenienaber — 2017-05-16T11:08:19-04:00 — #5
i am a little confused.
In MG you can set the numbers with 3 digits behind the period. This means all calculations are rounded at 3 digits In PM the value is rounded to 2 digits, so when you measure it in PM it is with 2 digits behind the period.
In PM everything you draw and save is converted internally to inches (which i hate by the way because it is causing so much troubles for us europeans).
You draft the macro and in PM the measurement you measure is 13.13 cm. Then you print it out and you measure again and you measue 13. So you think you lost 0.13 cm
You measure on the paper by hand with a ruler?
But how do you measure from the inside of the line to the inside of the line of the other side? Do you measure with the line or without. That is a difference and also in distance.
How can you measure by hand so presize 13.13 cm. I can maybe measure ca. 1 mm but not 1.3 mm.
Afterwards you have also work to do what is causing differences in the distances. You cut the pattern, it will change a bit. You have to cut the fabric and then sew it. I do not think that 1 mm in difference is causing any problems in the endresult.
I just did a test and draw rectangles of 10x10 cm. When I measure them it is depenent which ruler or centimeter do I measure with. I have different results. But when i measure with a cm and I measure from the middle of the lines it is exactly 10 cm. When I measure with a quilting ruler it is slightly off 10
Printing a pattern is dependent on the printer and the paper and also the humidity in the room. I have had that with my printer when the distance of the printed pattern was exactly right (I measured with a scale 1:4 ruler) and when i send out the pattern to somebody else the distances were on her printer a little bit off.This had to do with the other printer, how fast does it go, how presize is it.
Patternmaker does not control the printing.This is done by Windows and the printerbrand. PM just gives out the pattern to print to the printer driver. Maybe in the settings of the driver you can control the exactness of the distances.
I see also huge differences between the printing of the different brands of printers. The way they handle the printing is totally different.
When i would make a scale 1:2 pattern I would draw it in full size, so not give in half of the measurements but the whole measurement. And then scale the pattern afterwards in PM by 2. Then the rounding is much less i think.
It is also dangerous with al your formulas. When you have a formula of bustwidth plus 4 (90 +4)
and you give in the half of the bustwidth then the plus 4 is not divided by 2 (45+4=49 instead of 94:2=47)
cath — 2017-05-16T11:56:45-04:00 — #6
I am also a little confused, since I don't know what causes the problem, I search.
The fact is, it is absolutely sure that the printed draft is slightly different from the PM draft.
The line is so tight (1 pt), there is no error, I use my japanese ruler which is quite precise, and the problem is the same with my other rulers. And my draft represents the whole bust line, front and back assembled on this line, it is exactly 25.00 cms (12+13).
My formulas are right (and so right that in PM, the values are strictly correct with the dimension tool).
You are right, the difference is not important, but the sloper is without ease, so it very already tight on the mannequin when the measurements are respected ; and the point is I have to send the technical draft to my teacher and a diiference of 0.50 cms won't be accepted. So I had to draft it all again by hand.
I agree with you that the printer may change the values. I have worked with many CAD softwares, design softwares too, and I never had this problem (when I controlled the results), but yes, it is possible. I'm going to try with another printer when it will be possible ...
cath — 2017-05-16T12:29:07-04:00 — #7
I have just tried with another software (Valentina, an open source pattern sofware), well it is not exactly the same since I have drafted a rectangle which measures 12.13 * 13.13 cms. When I print, I obtain 12.1 * 13.1 cms.