topic Mix metric and imperial dimensions in one sketch? in Fusion Design, Validate & Document Forum

Mix metric and imperial dimensions in one sketch?

albertson.chris — Sat, 11 Nov 2017 01:06:13 GMT

People might consider the bad form but I want mix both systems of measurements of the same drawing. I have a part that is made of .375 inch aluminum plate and has holes spaced on 47mm centers. I'd like call out each dimension in it's natural units.

I was happy to find that Fusion 360 can do the inch <-> mm conversion for me. If the design uses inches I can type "47 mm" and Fusion shows 1.85 on the sketch. But what if I want it to show some dimensions in mm and some in inches.

The best I can figure out is to just use one system and then make notes that read something like "1.85 should read 47.0 mm"

One could argue that this problem is only cosmetic because the part is modeled correctly. It is, but one important goal of technical drawing is to communicate.

Re: Mix metric and imperial dimensions in one sketch?

mbostonsprint — Sat, 11 Nov 2017 01:48:27 GMT

You can add alternate dimensions by including them as additional text next to the primary units dims. Most often alternate units are enclosed in brackets. Many more sophisticated drafting and design programs have the ability to display and print alternate units as a part of the regular dimensioning scheme, but Fusion is not there yet to my knowledge.

I will say that anyone who is in the business of making things from drawings can easily do the needed conversions to any accuracy necessary.

Re: Mix metric and imperial dimensions in one sketch?

albertson.chris — Sat, 11 Nov 2017 17:03:23 GMT

Yes, of course anyone can do the conversion. But I want to make clear what
is being used. If I specify 9.525 mm thick aluminum it can be
converted. But what I want to say is "use 3/8 plate as it comes from the
mill" Yes I can put the words "use 3/8 plate..."

Actually 9.525 is wrong because it implies a tolerance of 0.001 mm. But if
I say 9.5mm then it looks like a "hard metric" dimension. Using the
faction 3/8 is very clear about what is to be used. Yes I know it goes in
the BOM.

Same with 47mm. If I use 47mm people with the relevant background will
see that is where a NEMA-23 motor goes because they use a 47x47 mm bolt
pattern. But if I specify the dimension as 1.85" then someone was to
suspect the male 1.85 is just under 50mm and maybe it is exactly 47mm and
if so then this part connects to a motor.

Is it looks like I'll just put the extra works on the drawing

Re: Mix metric and imperial dimensions in one sketch?

lichtzeichenanlage — Sat, 11 Nov 2017 20:16:00 GMT

@albertson.chris: Just to double-check: If you say sketch, you mean sketch like in the model environment or drawing?

Re: Mix metric and imperial dimensions in one sketch?

albertson.chris — Sat, 11 Nov 2017 21:12:23 GMT

Yes, I meant sketch as in modeling. I would use the "D" short cut to enter the dimension but eventually these dimension would cary over any place they might show.

Re: Mix metric and imperial dimensions in one sketch?

TrippyLighting — Sat, 11 Nov 2017 22:48:34 GMT

In the sketch environment the dimensions you enter are translated into the default units.

So say you have your default set to Imperial, when you enter a dimension into into the entry files as 25.4mm and then press the Enter key to accept the dimension will show in inch.

However, when you double click on the dimension to edit it the original value of 25.4mm will be displayed.