Does change scale to fit yes in print pdf change model or scale at print only?

print pdf of an object, window option, drag larger it asks to change scale, if no I cant get model to fir the A4 sheet, go yes then.
Has this changed my model scale, I am always troubled by any alteration or apparent alteration of the original 1:1 scale I draw at. If I say yes to change scale surely it changes scale of the model ?
I am printing an engine cowling to A4, so I presume it ends up at 1:5 scale or something !
Copy paste it into a previous file and it will sit there like a scale model beside the 1:1 one.
I do so yet its same size.
If the model is now at some odd scale how can I tell ? Is it at 1:5 but expands up when dropped into a 1:1 file ?

I still am scared when changing units from cm to inch as to what to pick on the change scale ‘ask’.
I always want everything I do at 1:1 scale, can never understand why scale has to change.
I want to be able to bring one model into another model file and they fit together etc. If it does expand up I am still uneasy over it not being 1:1 at source. If I have a paper plan at 1:1 scale and I scan and bring in, how will that be with it.


If you think about it, I believe you’ve answered your own question. I know there’s some things in Rhino that cause one to question one’s experience, especially if you haven’t used one of the commands in a while.

When you want to change the units of the MODEL, Rhino needs to know whether the original dimensions of the model in model units are in the starting dimension system or the destination dimension system. If the former Rhino will adjust the model units according to the conversion factor. If the latter, Rhino doesn’t need to do anything beyond changing the unit labels on the dimensions. This whole process can take place while the picture on the screen stays the same size, since that is strictly a function of the zoom level you’ve chosen.

When you print out a view of your model you need to tell the printing process what zoom level you want for the printed “display” on the paper. It’s effectively a separate zoom factor for a separate “display” system. There’s two different approaches to choosing the printing zoom (scale factor):

  1. You’d like the printed image to be the same physical size on the paper as the real object, or some particular defined scale thereof.
  2. You’d like the model image or some particular sub-part of it to fill a specific area of the page regardless of what the printed scale factor ends up to be.

The printing setup form allows you to use either approach.
The answer to your question is that the resulting printer “scale factor” is completely independent of the model “scale factor”.

That’s my story and I’m sticking to it because it works for me.