How I can Broke Metrics

Please i am having Problem with the Metrics, after doing spacing By Eye, the SIDEBEARINGS will be very very good. but once i update the Metrics with Ctrl,aIt,Cmd,+M. the Gaps in the SIDEBARING returns back to the previous stage, destroying my effort. please how can I solve this?

The command you mention reexecutes the metric keys, the formulas you put in the sidebearing fields, on all masters. See the Spacing tutorial for details.

It seems like in your case the metric keys are wrong or point to a glyph that has not been properly fitted yet. So I suggest to either space the key glyphs, and then update the dependent glyphs, or to delete the metric keys.

@mekkablue thanks, the Metrics keys are correct, i am using “H=50, O=H/2” with Steam weight of 100. but i have 3 Variables or Families to say, Thin-40W,Regular-100W,Bold-170W, at Regular no much the Metrics keys works fine, the metrics key fit in well, but in Bold and some Thin not well. and please how can i make two files into one Masters? I have one file with “Thin,Regular,Bold” and another file “Thin Italic,Regular Italic,Bold Italic” . Thanks

Then you metrics keys are not correct. And it doesn’t make much sense to have “=50” as a metrics key in the “H”, because that would always be set manually. If you really need that, you need to have layer specific metrics keys. It needs two equal signs in the beginning. So in the Thin, you might have “==20”, in the Regular: “==50” and in the Bold “==75”.

In the most cases, it is probably better to keep Italics and Uprights in separate files. You are not interpolating between uprights and italics, are you?

@GeorgSeifert Thanks very much, i could not understand well what you mean by layer specific metrics keys?. I started with “H” to used the suggestion from you. (20 for Thin, and 50 for Regular and 70 for Bold). still when i updated the Metrics in all the Glyph letters, is not fitting as i wanted. please may be any more information on what i should do? i want to delete the Metrics Keys to check again.

@mekkablue Thanks very much. all the Glyphs has be finished. is a two separate files with 3 Masters/3 Instance each. is it possible for me to make it as one Font with 6 families?
i could not understand this Question = You are not interpolating between uprights and italics, are you? please explain little bite more.

The uprights and the italics do not need to be in the same file, they just need to have the same family name.

Oh OK, thanks very @mekkablue, so if I want to upload it to a site, for a downloadable fonts to use for other App, so i do not need to combine the fonts to one file. sorry that i asked again, is for me to understand it well. thanks for giving your time.