The Modelspace or Paperspace Argument

William Forty
William Forty

I've been looking forward to this post, as this argument has raged for over 10 years between the many other CAD professionals I know. Ironically, the conclusion I have come to doesn't have much to do with which way is best. It is more of a philosophical conclusion about social behaviour and perception, explaining why this has remained unresolved for so long.

What we're talking about here is whether it is better practice to put notes and dims in modelspace with the model, or in paperspace, dimensioning or annotating on viewports. So that there is no ambiguity here, by "notes", I am referring to notes with a leader that point to something in the drawing; i.e.,  something that refers to the model. I am not talking about general notes that might be in the top right of your drawing frame for example.

In a nutshell, there are advantages and disadvantages of both working methods, and each are suited best to different situations. Using modelspace, notes and dims can be saved in an xref and reused across a range of drawings. There's no point in writing the same note more than once. This can sometimes add more complexity to whatever layering system you have adopted, as you may want to show or hide different notes on different drawings. The next argument for using modelspace is that dims and notes in modelspace is a more robust methodology, as there is less chance that the notes or dims will get disassociated with the object to which it refers. One of the main drawbacks of using modelspace for notes and dims is that we have to work with many text/dim scales so that they are displayed correctly through viewports in paperspace. This is to some extent fixed with the use of annotative styles, but this brings problems of its own, not to mention that there is generally a lack of understanding of this feature.

Conversely, by placing notes and dims in paperspace, we avoid the necessity to work with many scales. We can annotate and dimension the drawing using a single 1:1 scaled style. This arguably is simpler. However, working in this way loses some of the functionality that was available before, such as the ability to re-use the dims/notes. Also, a viewport that is moved carelessly can cause the notes and dims to end up disassociated with the objects that they are supposed to point to, which is not ideal, especially if it goes unnoticed.

So, which method is best? ...The correct answer is... that there is no correct answer. At least, there is no general correct answer. It depends on a number of factors such as project size. If you're working on a huge project, it is more advantageous to put notes on an xref where they can be reused on the many drawings that are required. On the other hand, for very small projects, there's no point investing extra effort in putting notes in an xref, when the xref is only used once or twice! In the latter case its usually far easier to just paint on your dims/notes in modelspace, without the need to pre-plan scales and layouts.

There is another factor to be considered. Imagine a person that has worked 99% of the time with notes in paperspace for 10 years. Chances are, they are going to be very adept at using this method. Also, chances are they are going to be much slower at working with notes and dims in modelspace. This is a valid point - it's not so much about resistance to change, its about people simply having more experience in working in a certain way. When asked to do it another way, it takes longer, and requires more effort (thought).

I mentioned at the beginning of this post that my conclusions have little to do with the actual discussion of paperspace vs modelspace. The most interesting things I've observed from this debate is how remarkably quickly people get wound up talking about this. I've seen people get really irate about this issue, claiming that anyone that thinks the other way is easier is <<insert creatively offensive adjective here>>. Usually though, the argument is based on an incomplete or incorrect understanding of how the other way works. For example, one modelspace user claimed his way was clearly better, because paperspace dims would surely not follow objects that moved in modelspace... a lack of awareness of the DIMASSOC system variable.

So basically I conclude that the reason this argument has raged for so long is mainly down to people having a lack of understanding of the benefits of working in the other way, which leads to a _perception_that their way is best. Convinced in the truth in their unfounded argument, this fuels the debate, and neither can understand the other's perspective. Until people broaden their horizons and accept the fact that they might be wrong, this state of perpetual disagreement will remain unchanged.

Thanks for reading, and please do subscribe below if you found this article interesting. You'll recieve an update via email whenever I post new content like this.



2011-10-23 23:17:01

After being away from Autocad, I've been brushing up with the 2011 student version and was breaking my head about the modelspace and paper space dilema when it comes to text and dimensioning, I read your post and found it, cut and dry, very helpful, bottom line I'll just keep myself with a dynamic attitude able to adjust: i'm just gonna learn to do it both ways thanks.

2011-10-24 08:20:07

Thanks for the kind words Carlos - it's good to be ready and able to use both methods. That's not to say that you can't favour one over the other though - usually the type of work you're generally doing will make one method slightly more favourable than the other.