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understanding drawing scale and scale factor


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ReMark

No you don't.

 

Draw all your model objects at FULL size no matter if they are paperclips, F22 fighter planes or the solar system.

 

When it comes time for your text and dimensions you can either put them in model space, utilizing annotative scaling, or you can elect to put them in your paper space layout at their normal size (ex. - if you want your text height to be 1/8" then that's the height you use).

 

You can have multiple annotative scales for your text and dimensions depending on the viewport scales you intend to use in your paper space layout.

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ReMark

Applying a scale factor to text and dimensions was quite common in the days before AutoDesk introduced paper space layouts and viewports and everything was done in model space. For example, let's say we were drawing a plan view of a house and ultimately it would be plotted at a scale of 1/4"=1'-0". The scale factor for our text and dimension heights would be 48 (1/4 * 12 or 4*12/1 = 48 ) So if we wanted our text to plot at a height of 1/8" it would have to be given a height of 6" in our drawing. (.125 * 48 = 6 ).

 

Is it possible you were thinking of viewport scale factors? There is a way to assign a scale to a viewport via the Zoom command utilizing the Scale option. It is referred to as the n/XP scale factor. As an example to assign the scale of 1/4"=1'-0" to a viewport the scale factor would be expressed as 1/48xp. Another example: a scale of 1/8"=1'-0" assigned to a viewport would be expressed as 1/96xp.

 

While many older users might remember and even use this method AutoCAD now makes it easier to assign a scale to a viewport by selecting it directly from a Scalelist.

 

Are you using metric or imperial units?

 

What scale or scales were you planning on using for your drawing?

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cwdesign

Applying a drawing scale factor does not change the scale I draft in. I will still be drafting 1:1 in model space.

 

At the firm I worked at when I drafted on AutoCad (ten years ago - I need to relearn it), everything was done in model space. Sheet borders and plotting were done in model space. It may be different with the newer AutoCad programs, but, for my purposes, I will just be working in model space. I'd rather not worry about viewports until I know that I can use all the AutoCad drafting features again.

 

I will be drawing a 5,000+ S.F. house and I will want to use dimensions and text as I go along. I know there is a command to put in a drawing scale factor. I used it successfully once, but I failed to write it down and now I have forgotten it and I can't find it in the book again.

 

I will be using imperial units. 1/4" = 1'-0" Therefore, the drawing scale factor is 48. What command do I use to put in the 48 drawing scale factor?

 

From the book "AutoCad 2010 for Dummies" by David Byrnes:

drawing scale.jpg

drawing scale2.jpg

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JD Mather
I will be using imperial units. 1/4" = 1'-0" Therefore, the drawing scale factor is 48. What command do I use to put in the 48 drawing scale factor?

 

Forget about scale factor.

You don't need it.

 

Draw house at 1:1 scale (just like the real world).

 

On the drawing board the boarder/titleblock was 1:1 on paper. (it is what it is)

Your layout will be your paper with the boarder/titleblock on your layout just like the real world.

 

Someone will come along and tell you how to create your scaled viewport on your layout (just like the real world on drawing board).

Actually AutoCAD does it for you so it is all so easy. You need only think in 1:1 real world and the program takes care of the view scale for you.

So Easy! No calculations needed. For those who can't figure out how to scale something - this is great news.

 

BTW - 10+ years ago this was the only correct way to do it as well.

 

Notice that

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JD Mather
Without the drawing scale factor set, I will not be able to read the dimensions and text - they will be too small on the screen. I would have to define text height in feet. Then, when I do want to plot, the text would not plot correctly.

.

 

In this century AutoCAD takes care of that for you. You need only think in 1:1 - the real world.

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Professor Mather, may we quote you on that?

ReMark would you concur with JD's assessment?

Me too.

While it may well be unsettling to hear that your chosen reference book MAY be espousing dated approaches

(although not necessarily lacking as previously postulated),

and while the information you are culling from the best cad website in the solar system flies in the face of

David Byrnes' technique, JD & ReMark have about 33,000 posts on this site alone between them (helping people with questions or cad problems, like yourself)

and more years using the programs than either of them would care to admit.

In fact the only reason they are on this site is to help those who need it,

and they are really well informed, and generous with their time and expertise.

We all want to help.

I hope you figure it out. :)

Edited by Dadgad
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Should delving into annotative dimensions (created in model space) seem too daunting, then you can do all of your dimensions in paperspace.

To do that you would create a DIMSTYLE consistent with the scale of the viewport scale in paperspace

(remember to lock your viewport after you get it set up and zoomed to the appropriate size).

I do my dimensioning and all text annotation in paperspace, leaving only the drawing in modelspace.

When setting up the DIMSTYLE you specify exactly how tall the height of the dimension text should be.

creating a dimstyle.JPG

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Perhaps this will help you, these are some of the DIMSTYLE dialog pages on which you create a new dimstyle.

The blue line in the image is the edge of a viewport which I have set to display at 1:8, and locked, so that value is set.

I have then created a new dimstyle by copying an existing dimstyle, and giving it a new name.

The name I have given it is "8" , being the reciprocal of the scale 1/8.

On the primary units tab I have set the SCALE FACTOR for this dim style as "8".

 

As I do my dimensioning in paperspace this is an appropriate dimstyle to use on a drawing which is being displayed in a viewport of 1:8. Now I can just turn on my OSNAPS and get to work.

I hope this helps you a bit, come to grips with using paperspace, viewports and dimstyles. :)

setting up a new dimension style.jpg

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mor424mont

I had to face same problem like you when I was new. You can improve your dimension quality by studying or taking the help of video tutorial which are available on Internet. You may checkout www.lynda.com for this purpose.

 

Regards,

mor424mont | offshore merchant account

Edited by mor424mont
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ReMark

cwdesign: I am familiar with the method that you refer to and fully understand what you are attempting to do but that method is now considered to be outdated and inefficient. By learning about paper space layouts, viewports, annotative scaling and alike you will be updating your skills and working more efficiently. While it is uncomfortable abandoning old skills for new in the long run you will be doing yourself a huge favor if you follow the advice we are attempting to give you.

 

There are tutorials here and elsewhere that will acquaint you with some of the topics we have discussed thus far.

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JD Mather
While it may well be unsettling to hear that your chosen reference book is somehow lacking,...

 

I don't see enough information to determing that it is lacking.

In fact, it starts out by stating "two ways" and "traditional".

It reads like it is going to get into proper technique once the hows and whys are covered (important for someone coming from old-school techniques to get their head around modern techniques).

I do not see where it continues to describe the modern technique in using CAD in any depth.

I assume a close further reading of the book (if it was written in this century) will describe modelspace/paperspace correct and proper use.

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JD Mather
.... While it is uncomfortable abandoning old skills for new ....

 

...and since the old skills seem to have been forgotten (thus the very question posted here) - it is a natural time to learn the new.

I find it much harder to teach someone a new way when they really really know an old way.

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redbeardcad

I guess I'm an old schooler and only do this part time. So, to help me understand; Is it better to dim and text in PS? When I am drawing something I need to have some dims so I know what length it is and to have to switch back & forth from MS to PS seems like a hassle. Maybe if I have the dims on a layer that won't print in MS then PS can be what ever.

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Dimension redundancy in model and paper space will just be a waste of time and could possibly cause problems down the road. One can always use the Distance command to check a dimension.

 

I don't know what the percentages are but you'll find proponents and opponents to dimensioning and placing text in model or paper space. I say try each and make your own decision. My personal preference is for paper space but I could see real benefits to doing it in model space for some disciplines.

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redbeardcad

You're right. I have done mostly MS dims with titles and tags in PS. But where I get messed up is dealing with architectural one day machine the next and then working with civil throws me way off. So PS and annotative text might be the best way to handle all the different scales.

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Annotative text and dimensioning is best suited for model space not for your paper space layout. Placing text and dimensions in your layout would be the same as doing it manually on the drafting board. You want text that is 3/32" high that's what you use. You want arrowheads 1/8th" long that's what you draw it at. It is literally 1:1.

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Annotative text and dimensioning can be done through a viewport in your layout or you can switch over directly to model space and do it. Makes no difference as far as I can tell. You'll just have no have some idea of the annotative scales you'll be wanting to use based upon the scales assigned to your viewports (assuming you'll have more than one).

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JD Mather

I am a proponent of Modelspace/Paperspace, but (hold on to your seats) I do all of my dimensioning in modelspace (if I have to use AutoCAD).

I have tried annotative dimensioning several times (but not in the last couple of years that I have not really used AutoCAD) and gave up on it becuase of some serious "bugs" (in my opinion, but then I'm used to using Inventor).

 

As I recall you had to be very careful about moving model or dimensions became unattached.

As I recall there was a serious problem with centerpoints not scaling correctly.

 

Others with more experience in AutoCAD annotative dimensioning will guide you here, but I just wanted to point out that modelspace dimensioning is perfecty robust and relatively easy to set up. If only annotative dimensioning worked as well as it does in Inventor.... ....well maybe it does now. I have to teach an AutoCAD class this fall after a couple of years away - so you experienced users set me straight on current functionality.

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redbeardcad: If you want to read some tutorials on the use of Annotative Scaling as it pertains to text and dimensioning I can provide you with some links.

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