dwg ltscale - can someone explain

I'd like some background and good practices about this command/setting.

Both when working in dwg-files. And when exporting from dgn to dwg.

  • Hope other readers will be able to chime in and offer their good practices, but I can provide some background on this.

    Every single linestyle (aka linetype) in ACAD is of a custom line style, including Continuous.  Since a custom linestyle has stroke/space length in file units, you can apply a scale to it.  This is true in both MicroStation and ACAD.  LTSCALE is a global scale factor that applies to all linestyles that do not have an explicit scale factor.  This global linestyle scale is per file in ACAD and per model in MicroStation.  When you open a DWG file, all models have the same global linestyle scale.  When you save a DGN file as DWG, the default model's scale gets saved as LTSCALE.  This is because ACAD only stores one LTSCALE in a file.  If you need a particular LTSCALE in a saved DWG file, you need to set that value prior to your saveAs operation.

     



  • Thanks a  lot Don.

    File units - mine is mm - but I wonder what will be 1 mm - but some experimenting will show.

    And global + per linestyle - that explains a lot.

    Exporting to dwg takes the scale of the default!! Model - that is important when you push DVs Drawing Models to separate files!

    regards / Thomas Voghera

  • Hi Thomas,

    I wrote a short explanation of the LTSCALE setting for Microstation user when V8 was introduced:

    http://communities.bentley.com/communities/other_communities/askinga/w/askinga/ltscale-for-microstation-users.aspx


    I think it is still appropriate.The LTSCALE controls the display of non-continuous lines in DWG files (these are fixed in their display and printing in DWG files, not dynamic as in DGN files). The setting is a bit of a 'suck it and see' item because even Autocad user don't seem to pay much attention which line-type scale file to use (imperial or metric).

    Regards,

    Lincoln

  • One problem is annotation scale. We are a dual CAD shop. sometime before AutoCAD 2008, AutoCAD introduced their Annotation scale. And somewhere in that lineage, they introduced PSLTSCALE and then MSLTSCALE.

    So in our office, we set LTSCALE to 1. We set MSLTSCALE and PSLTSCALE to 1. Then, we set our Annotation Scale to our plotting scale. When in ModelSpace, the linetypes look correct. When we are in PaperSpace, we scale or modelspace viewports down and the linestyles look correct.

    It should be noted, that at a different employer, we actually scaled our sheets up, just like we do in MicroStation. This actually works just as well as the other approach.

    Anyway, we cannot recreate this workflow in MicroStation using DWG workflow. At this point my use of MicroStation on DWG projects is limited to a very specific workflow and at the end, the file is either converted to DWG to its design elements are exported to LandXML and brought into Civil 3D.


    Charles (Chuck) Rheault
    CADD Manager

    MDOT State Highway Administration

    • MicroStation user since IGDS, InRoads user since TDP.
    • AutoCAD, Land Desktop and Civil 3D, off and on since 1996
  • LTSCALE and PSLTSCALE are the two functions which can effect how your linetypes are printed.  There are some other varials that unless you have messed with, the default settings are typically not necessary to change.

    LTSCALE will set your global linetype scale.

    PSLTSCALE will tell Paper Space (your sheet) whether to interpret your Line Type Scales using the LTSCALE or not.

    PSLTSCALE = 1 (will scale LTSCALE to paperspace based upon your VPSCALE of that viewport)

    PSLTSCALE = 0 (will use current LTSCALE without any manipulation)

    I generally set my LTSCALE to .75 and PSLTSCALE to 1.  This typically results in the best prints for me.  I suggest using PSLTSCALE of 1 and manipulating LTSCALE to your liking (you will need to regen after each change to see the updated scale).  The only problem with this is if you have large scale items, such as 1" = 20' or more, your Model Space LTSCALE will be so small that you may not be able to see it.  I just got used to it this way.  I wish AutoDesk would change it and have MLTSCALE and PLTSCALE to manipulate the linetypes shown in both Paper and Model independently.

    Hope that helps.