Associative Dimensions Changing in Paper Space 1

[chasj]

Has anyone encountered an instance when an existing associative dimension in paper space changes its dimension value? This has happened to several of us in my company more than once when we zoom in or out in paper space, switch from one layout to another, after plotting, or at other times. It seems to happen randomly in only some drawings, only to some dimensions, and only in some viewports. Very mysterious. And dangerous.

For example, I recently found a dimension on a drawing reading 3/8" instead of the 3" it was supposed to be. It had been placed in paper space in a viewport with a scale of 1 1/2" = 1'-0" and associated with an element in model space. When checking its properties I found its dim scale to be 1 instead of the -8 it should have been. All the other dimensions in that same viewport were fine.

Any suggestions?

 

[pmkPE]

The only time that I have a similar experience is when I unintentionally pick an entity that is in paperspace, not model space. For example if I have dimensioned an entity in model space and then I try to pull off another dimension and accidentally pick the paperspace dimension extension line it gives me a resultatnt dimension based on paperspace units. Also, this occurs if you try to run a dimension crossing over more than one viewport. AutoCAD will give the resultant dimension in paperspace units.

 

[cadcoke5]

I've had similar problems with both Acad LT '97 and full version Acad 2002. Existing dimensions that read correctly when they were created will later spontaneously forget their values. I should point out that there are two different types of associative dimensions you can have in paperspace. My "forgetful dimensions" were the old-style associative which depended on you creating a dimension style that had the scale factor already set. The newer "transdimensional" (which was supposed to automatically scale the value for the distance)had its own problems, like not working on some entities.

It appears that paperspace dimensions will never be fixed by Autodesk and are going to fail intermittently. In general, Autocad seems to have lost its reliability over the last several years.

Joe Dunfee

 

[RiBeneke]

Associative dimensions in paperspace must have their nodes anchored on a point over the object being dimensioned.
In other words, you can dimension to endpoints, centres etc and the dimensions usually keep their place.
However you cannot use coordinate filters (.x of and .y of etc) if the dimension node is then placed away from your model space object. You also cannot use 'perpendicular to' fo placing dimension nodes. If you do, then the dimensions lose their places when views are regenerated or the drawing reopened.
I do not know if the problem has been fixed in AutoCAD 2005. The problem makes paperspace dimensions rather useless for all but the simplest of drawings.

 

[IFRs]

I have had great sucess with paper space dimensions of model space entities. I am very careful to snap to model space entities. Also, be sure to set DIMASSOC to 2. We use R2004 on Win2000 and WinXP machines.

 

[cadcoke5]

While snapping to objects is necessary, the problems appear even when you do that. The only way I know of, which seems to be reliable is to not snap to the object, but rather select the entity. I.e. select the whole line to dimension, rather than its endpoints. This process will fail on objects that transpacial dimensions don't like. This way, at least, you know that your dimension is invalid.

For me, 95% of my entites are things that version 2002 doesn't like for transpacial dimensions (solids and polyface meshes), So, they are useless for me. I know upgrading will fix SOME of the transpacial dimension problems... but that is why I upgraded to 2002 in the first place. I've lost the desire to continue upgrades for bug fixes. They don't fix bugs, they only shift them around for you to hunt for.

Joe Dunfee