Dimscale Linear won't retain its value in paperspace dimensions

I have been having this problem for years, and nothing I've found has been able to fix it. I'm trying to dimension a solid model through a paperspace viewport in AutoCAD Mechanical 2009, and the value for "dimscale linear" seems to have a mind of its own. Sometimes it randomly changes to a huge number. Usually, it reverts back to the incorrect value as soon as I try to change it in the properties window; but sometimes it will allow me change it, only revert back to the false value again after a dimregen.

It seems to be caused by dimensions that have been located using specific osnaps. I tested out each osnap individually, and the only ones that were able to preserve the dimscale linear value after a dimregen were: node, intersection, extension, tangent, apparent intersection, parallel, and rectangle center.

I have been using a custom ampsnap configuration of just these osnaps for whenever I need to add paperspace dimensions, but they still aren't always reliable. I still have to do a dimregen after every dimension I place, just to make sure it will hold its correct value.

Is there a safe way to dimension solids through paperspace viewports, or should I just try to revert back to using annotative modelspace dimensions?

I've always stayed away from dimensioning in paperspace and think it might be better to dimension in modelspace to be honest. I'm not too familiar with your version, but i guess the fewer variables for error introduced the better. Sorry if this isn't the answer you were looking for.

I dimension in paper space all of the time and never had much of a problem, but like you mentioned only certain snaps work well with associated dimensions and there are some limitations.

You can also use _DIMREASSOCIATE to make sure the dimensions are associated to proper points.

You may need to use DIMREGEN to update associative dimensions after panning or zooming with a wheel mouse, after opening a drawing that was modified with an earlier release, or after opening a drawing with external references that have been modified.

 

Although associative dimensions support most object types that you would expect to dimension, they do not support the following:

 

• Hatches
  
• Multiline objects
  
• 2D solids
  
• Objects with nonzero thickness
  
• Images
  
• DWF underlays
  

When selecting objects to dimension, make sure that the objects that you select don't include a directly overlapping object that does not support associative dimensioning such as a 2D solid.

 

Associativity is not maintained between a dimension and a block reference if the block is redefined.

 

Associativity is not maintained between a dimension and a 3D solid if the shape of the 3D solid is modified.

P.S. There is a long list of known bugs with 2009, make sure you have all of the updates, fixes and service packs.

I running on SP3 right now. I did find a fairly reliable workaround, though. Setting the visual style to 2d wireframe makes the osnaps work a lot more consistently. Now I'm just shading the final plot as 3d hidden, and also getting a good performance boost out of it