Scale questions in AutoCAD

[mdmurphy]

If possible, could someone lend me a hand with determining the scale of a particular drawing? I need to start development on a site model with context and need to get the scale aspects perfect. I have spent some time trying to determine the scale for myself and have been thus far, unsuccessful **little background - intro:)**.

 

Can someone explain how changing the scale of a drawing affects the dimscale? I gather they are directly correlated - as I change a drawing to 1/8 scale and when I type in dimscale at the command prompt the return statement gives me 8'-0"..so every inch related to 8 ft. This is correct?

 

Next, can I change a drawing back and forth between different scales without any detrimental side effects?

 

Lastly, Once I figure out the drawing scale, would it be reasonably to assume that I could setup limits on a specific site of my topo map and place a grid over it to better relay my the dimensions for my sitemap on a piece of foam core?

 

If this doesn't make any sense let me know.

 

Thanks, in advance, for any insight that anyone could offer.

[David Barbarash]

I'm assimung that you're using a version of autocad 2000 or later. If so, then you should NEVER change the scale of your main drawing in model space. Keep it at 1:1 and change your view scales in paperspace using wither a zoom xp command or the handy dandy pull down scaler on the viewports menu. As for dimensions, I usually set the text (in model space) to be legible at the smallest scale you'll be printing at. So if you have a drawing showing sections at 50, 20, and 10 scale. Make sure they're legible at 50 scale first, then see if they're not too big at the other scales. If they are, look into dimensioning in paper space using the dimscale that you mentioned earlier. Simscale will multiply or divide the actual measured dimension of a line/curve by the number that you enter in order to show a real world dimension. Hope this all makes sense.

 

David Barbarash

[Chad Warner]

Wouldn't be easier to work at full scale in the drawing and then plot to particular scale? I'm assuming you want to work on only one area of your site that would fit onto a 24x36 size piece of foamcore, correct? If thats the case, go to "Layout1" (assuming you are using ACAD2000 or above) and create a 24x36 sheet of paper, using a scale of 1:1. Type Mview, then fit. Then type "mspace" to get you to the model space. Then type zoom, choose scale, then type ".0104xp" for eigth scale (1/96 = .0104). Once you have the scale setup, you can pan around the drawing in modelspace until you get the area of the drawing you want, then plot at full scale.

 

Hope this helps.

 

-Chad

[kainoa]

I agree with these guys, keep everything at 1:1 scale in mspace and zoom your pspace viewports to the scale of your liking. Do your dimensions in mspace and set your dimstyles to reflect your pspace scale.

 

If it's a large site plan that you're working with (talking acres here) than to make it easier on yourself you can work in feet as opposed to inches.

[Kerry Thompson]

Hi Michael

As others have said, AutoCAD uses real world units and should not be scaled in model space. That said the “units” command defines the measurement units assigned to the drawing units. In New Zealand, we typically assign millimetres to each AutoCAD unit, in imperial; inches may be assigned as the drawing unit. You also have to watch for precision issues, for example using inches to represent a project covering square miles may have rounding errors, especially for points well away from 0,0,0.

The dimscale variable controls the size of the notation entity in the dimension style, i.e. a dimension viewed at 1:96 would have a dimscale of 96. (dimassoc is set to 0 or 1)

 

Different view scales are set-up using viewports from layouts as described above.

 

Hope this is of help

 

Kerry

[Fernando Lino]

if you are working with architectural plans 1:1 if you want engering but working in inches 12:1

if you want metric system 1000:1

 

Other way is working in ADT and setup different display per scale and use AECdimensions then the dimension is relative with the scale.

 

or more simple...use REVIT!!!!