Why can't I have a 1:4 drawing scale?

[Stivie886]

Hi guys,

I've browsed the forum a bit but I can't find the answer to this... I have been using Creo for a while now and always bypassed this problem by using different scales that Creo accepts, but it is getting very annoying... Why is it not possible to have a drawing scale of for example 1:4, which is an absolutely normal drawing scale to use, no??? When I try to use a 1:4 scale, it will always change it to 3:10, which is a horrible scale. Seams like Creo converts this into decimal in the background (0.25) and then rounds it up to a single decimal digit (0.3) which is 3:10. Does this have something to do with a setting in my .dtl file? I have been looking for an option that would affect this, but I couldn't find one... I've been playing around with the view_scale_denominator and view_scale_format settings but I can't get it to work... Anyone knows the answer to this?

Thanks,
Steven

 

[robertib]

I believe Creo will not permit it because the standards do not allow for it. The standard denominators allowed are 2,5,10. Even though 1:4 looks like a simple choice, I don't know why the standards leave it out.

 

[Stivie886]

Hi robertib,

That is quite possible, even though I have never heard about that one... Everyone must admit that being able to use a ridiculous scale like 3:10, but not 1:4 is just absurd... Normally, according to standards you would also have to use ISO fonts, but Creo does allow you to use TrueType fonts, which I have fully embraced and our suppliers as well since it improves drawing readability so much.

Thanks for your reply Robertib, and not that I doubt your answer, but if anyone knows how to enable using a 1:4, 1:8, ... drawing scale, even if it means using some workaround, please let me know!!

 

[per2fh]

Stivie,
make sure in your .dtl file, you have the settings:

view_scale_denominator 100
view_scale_format RATIO_COLON

if view scale denominator is set say for 1, it will round your .25 to .3 making the scale 3:10

 

[Stivie886]

Hi Ron,

That worked! Thanks a lot for that! I guess I had a wrong understanding of how exactly the scale denominator works!

This forum and the people contributing here are absolutely fantastic!

Thanks again

 

[per2fh]

I believe Creo will not permit it because the standards do not allow for it. The standard denominators allowed are 2,5,10. Even though 1:4 looks like a simple choice, I don't know why the standards leave it out.

Robertib,
My intention is not to call you out but to clarify a statement you made and unfortunately, so often made by others.
The standards for scale is not defined specifically. The standard, according to ASME Y14.100-2004, section 4.23, simply stated, drawings shall be drawn to a scale that depicts all details of the item clearly and accurately.

Companies often create in house standards that designate recommended drawing scales. I believe this is where the misnomer occurs.