LTS scale issue

I have a drawing that I have drawn insulation on in several cross sections using the batting line type. Today when I opened the drawing, the insulation is at a much smaller scale in modelspace (3/8" instead of 6"). It appears fine in paperspace. I have compared the properties to the same thing in another drawing and from what I can see everything is the same, but in the other drawing it is displaying correctly in both model and paperspace.

Any suggestions on what may have caused this?

Thank you

Check these system variables. LTScale sets the global scale for linetypes. MSLTScale, when set to 1, means linetypes in model space are drawn at the drawing scale, in other words, you'll see what you would see in a viewport. PSLTScale works like MSLTScale only in paper space, and you have to set it for each layout. When you set MSLTScale or PSLTScale to 0, you see the LTScale only. And of course you can change the scale of individual lines, so it gets confusing.

A good rule of thumb is...

PSLTSCALE = 1 (in each layout)

MSLTSCALE = 1

LTSCALE = 1 (or some factor close, we use 0.5)

Then just make sure your viewports and MS scale factors are set correctly.