Whether to Dimension in Model Space or in Paper Space

It seems to be a matter of personal preference. November 23, 2008

My understanding is that if I dimension in paper space, I don't have to deal with layers for the different dimensions relevant to the viewport. My understanding is that if I dimension in model space, I don't have to deal with scaling. This way seems safer if someone else needs to dimension a drawing I did. Which do you prefer and why?

Forum Responses
(CAD Forum)
From contributor J:
When drawing 2D I prefer to dimension in model space. I’m always checking dimensions, so why not just do it once? I do use the distance command sometimes, but why go through the process 10 times when you can dimension once, because typically you’ll need to later anyway. Also when I or someone else opens the drawing for field dimension changes, it's easer in my opinion. Although the other way you can work through a viewport, but there are problems if you have to stretch an object beyond the viewport window. I also use a program for putting objects into paper space that will automatically make the viewport, scale it, and put a label below. So my process is: I draw and dimension in model space. Then put everything into paper space. Then arrange my viewports. Then label like a madman. Then plot. Then have a beer.

In 3D I sometimes dimension in paper space due to the various isometric views. The only thing is that the dimensions are not associated with 3D solids, so if you stretch a solid, the dimension will not change.

All of this works for me because I draw for a lot of different companies that have their own in-house draftsmen, and 99% of them freak when you do it the other way. The bottom line is: If you are comfortable with the way you dimension and there are no complaints, just keep on a rockin.

From contributor D:
Great Scott! Always in model space!

From contributor N:

It's been a long time since I used model space for dimensions. The main reason was that paper space dimensioning eliminated changing the dimension scale for the view. We used a lot of view scales and it became a royal pain. Paper dimensions can be set to automatically scale to viewport scale so one style setting worked for all.

Once we went to 3D, model space dimensioning became virtually impossible. We also do not provide drawing files for others' use. We will publish a dwf, pdf or paper plot for customers. This means we don't have to worry about what others prefer and aren't guided by this.

It's the same old same old. Everyone will prefer what they learned and are used to.

Contributor J, try setting dimassoc = 2 for your 3d dimensions.

From contributor S:
I dimension in model space, 2D and 3D. Dimensioning 3D in model space is very possible - I do it all the time with great success. I think that dimensioning in paper space is a big mess. Depends on draftsman, perhaps - some draftsmen use lots of dimensions, some just a few.

From contributor G:
I dimension in model space as much as possible, and in paper space for 3D. I have found many instances where you need to dim in paper space in 3D. A good example is a "U" shaped room. We routinely use clipped viewports. One for the plan view underneath the counter, one for each elevation that can't be seen otherwise. If you attempt to dim in model space, you end up with dimensions all over the place. While you could create many different dimension layers, and freeze all the ones you don't want, per viewport, that seems very cumbersome.

I prefer the clipped viewports over the section plane command because the view remains linked, so any modifications only need to be changed in one spot. Section plane command really shines if you've got to really detail an area, though.

From contributor S:
I don't use 3d drawing as view for 2d layout. I do "solprof" to generate my 2d elevations and "section" to generate my plans and sections. If I need to show isometric or perspective view with dimensions, I do dimension my object in model space.

From contributor B:
I prefer paperspace dimensioning, because I find it a great time saver. With dimassoc set to 2, you only have to worry about one dimstyle and one dim layer. Your dimensions are associated and update automatically as long as you don't delete the entity that has the dimension associated with it. That said, it's really a matter of personal preference. The choices are there so you can do what works best for you. I suggest giving it a try. Make an educated decision based on personal experience.

From contributor L:
Paper space because of scale and lots of 3D.

From contributor U:
Model space.

From contributor H:
Contributor J, what you said about that program is very interesting. Does it automatically switch off dim layers depending on the scale of the viewport? If so, please tell what the program is. When doing detailed drawings, I often have 1:5 and 1:100 dims on the same drawing and have to switch off layers independently in each viewport!

From contributor J:
The program I referred to is in the Quick Draw 5.0 package. Located at jmhsoftware.com. I typically use two different dimension layers - one for regular dims and one for detail dims. I'm guessing that is what your 1:5 and 1:100 are.

The program is designed to use the layers in the Quick Draw package, but they are user friendly and can be set to any layer. When it makes viewports for elevations, sections and plan sections, it freezes the dim2 layer in the viewport and when making a detail viewport, it freezes the dim layer to help with what you're talking about.

There is a demo video on the website called “place scaled views into paperspace with viewlables.” Watch it and you will get an idea how it works.

The newer version is much better - it has tracking abilities, so once an object has been put into paper space and is moved in model space, you can update the paperspace viewport to go and find the moved object and rescale it into the existing viewport. It will also place a frame and label around the model space object that is red and once it is in paperspace it turns green so you can easily see what objects have been sent to pspace and which ones need to be sent. It does a lot more. You should check it out.

I also have a program for making quick detail viewports off of existing viewports, also available in 5.0. Once you have a viewport in pspace and want a quick detail blow up, it makes a circle viewport of the selected area to whatever scale you choose. I am currently updating all my programs and the 5.0 packages will be available for download next week.