Model Scale vs. Viewport Scale vs. Plot Scale?

I know that in Paper Space I can have various Viewports with different scales. Ok, capiche.

But why would I need a scale in Model Space? How does that affect my viewport scales? The only reason I can think of is if I'm dealing with Annotative text and I want to work in Model Space and see what it'll look like? For instance, right now my text is set to be 0.2 in Paper Space, and yet when Model Space scale is 1:1 the text is sooo tiny I can't even read it. So if i boost my Model Space scale to 1:25 the text gets much clearer.

Is that a reason why people would change their Model Space scales?

Also, in Page Layout Manager, I can also define a PLOT SCALE for the page I'm printing, so what does THAT do?

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Also, something that BUGS me...

I have many different files, in some my annotative text is 0.2 Paper Height, and some others it's 2.0! And sometimes I'll import the same block into 2 different files, and in one it'll be 10x too big and in the other it'll be fine... Does this have to do with the Plot Scale or what? (INUNITS all set to cm!)

First rule of AutoCAD Scale Club: Draw all your model space geometry at FULL size. It doesn't matter if you are drawing something the size of a paperclip or a Boeing 787 Dreamliner or the Milky Way. FULL size. Capiche?

We are not back in the days where we used drafting boards and everything (well almost everything) one drew had to be "scaled" to fit on the piece of paper we were going to use.

With Model Space Scale I assume you mean the little box at the bottom right corner of your screen where you can set a scale from the ScaleList? That only changes the annotative scale, and affects what annotative scales are added to your annotative objects. If you don't use annotative scale, then you can ignore that box.

Plot Scale changes the scale from your Paper Space to your plot device. For instance, if you have an A1-drawing and want to plot it on an A3-sheet then you only need to change the Plot Scale in your PLot dialogue box to 1:2 and you are good to go.

Also, something that BUGS me...

I have many different files, in some my annotative text is 0.2 Paper Height, and some others it's 2.0! And sometimes I'll import the same block into 2 different files, and in one it'll be 10x too big and in the other it'll be fine... Does this have to do with the Plot Scale or what? (INUNITS all set to cm!)

The files probably have the Annotative Scale set to different values. What you are referring to as Model Space Scale is actually Annotative Scale as Tiger already mentioned.

Another possibility is that the files have a different value assigned in the text style.

Hm, this makes sense...

ReMark, don't worry, all my drawings ARE in full size...

So if I mess with the Scale box in the lower right of the model space it'll just update all the ANNOTATIVE TEXT stuff? What's the difference between adding Annotative Text while in Model Space vs. adding Annotative Text while in the Viewport?

Not much if anything. It might add the scale of the viewport automatically.

RobDraw- I have that problem often... annotative text looks fine in Model Space but is invisible in viewport until I go back to Model, highlight text, and then Add the specific Annotative Scale (which is pretty annoying).

Tiger- thanks for explaining about Plot Scale... I still don't 100% get it, but it's slightly better than before.

I still can't figure out why (for the same print-out effect), I need to set Paper Height to 0.2 for some files and 2.0 for others. Arg!

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But why would I need a scale in Model Space? How does that affect my viewport scales? ......

 

Is that a reason why people would change their Model Space scales?

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You should set the following variables to 1: MSLTSCALE, LTSCALE, PSLTSCALE.

The MSLTSCALE will use the Annotation Scale to display your linetypes in MS. Toggling back and forth from MS to PS works well this way as you always have the linetypes displaying properly.

LTSCALE is the global scale for linetypes (many use .5), others diagree and use 1.

PSLTSCALE will cause linetype dashes and gaps to appear the same regardless of the viewport scale.