INSUNITS Unitless is reset on open in Civil3D

[Anonymous]

Hello,

I have found a very interesting issue with Civil3D. If I create a drawing (DWG/DXF) in (plain) AutoCAD or AutoCAD LT and set the INSUNITS to Unitless, then open it in Civil3D and check INSUNITS they are reset to Meters. AutoCAD or AutoCAD LT handles Unitless properly and does not change it on open.

Does anybody know why is this happening in C3D? Any particular setting that might change this?

Simonas

[AllenJessup]

I tried it and this happens to me in C3D 2017. I created a drawing in AutoCAD and set INSUNITS to 0. When I opened it in Civil 3D. INSUNITS were set to 2 (Feet).

Now this is a presumption. Civil 3D is not a unitless program. It is either going to work in Meters or Feet. So I'm thinking the programmers made it to detect what your usual (or last) MO was and assign the INSUNITS accordingly. 

[Dexterel]

you can try to freeze this variable in Civil 3D through SYSVARMONITOR.
Try checking in AECDWGSETUP to not scale objects from other drawings

[Anonymous]

One thing that is interesting and what might break the statement "Civil 3D is not a unitless program. " is that if you save Unitless in C3D and re-open in C3D it doesn't reset the value.

[AllenJessup]

I think that means you can fool the program (or the programmers). I don't think it invalidates the statement. 

[Dexterel]

set to unitless

[Anonymous]

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@Dexterel wrote:

set to unitless

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It is set to unitless - same behavior. 

[Dexterel]

please upload an empty dwg crated in LT for me whit insunits set to 0.

[Anonymous]

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@Dexterel wrote:

please upload an empty dwg crated in LT for me whit insunits set to 0.

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Attached DWG with INSUNITS unitless.

[cwr-pae]

The change has to do with C3D setting units for C3D objects/functions when "converting" a vanilla ACAD dwg to C3d dwg on open as indicated by @AllenJessup's second post. If you always want C3D to use insunits =0 you can add the following statement to your ACADdoc.lsp:

(setvar "insunits" 1)

If you don't have an ACADdoc.lsp you can create one in the first support path for C3D using notepad or similar ASCII text editor.

What gets me is some drawings have the C3D units set to inches when I open them, not only is that option not normally available but it should be corrected by the conversion process.

[Anonymous]

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@cwr-pae wrote:

The change has to do with C3D setting units for C3D objects/functions when "converting" a vanilla ACAD dwg to C3d dwg on open as indicated by @AllenJessup's second post. If you always want C3D to use insunits =0 you can add the following statement to your ACADdoc.lsp:

(setvar "insunits" 1)

If you don't have an ACADdoc.lsp you can create one in the first support path for C3D using notepad or similar ASCII text editor.

What gets me is some drawings have the C3D units set to inches when I open them, not only is that option not normally available but it should be corrected by the conversion process.

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Is there a way to keep vanilla AutoCAD INSUNITS value when opening? Force use some value seems to be more of the workaround locally.

We are working on a software that exports DWG/DXF and expects C3D to honor the settings we write to file.

[cwr-pae]

If the issue only occurs the first time you open a drawing in C3D, opening the file in C3D, setting the variable and saving once should do the trick. Thereafter C3D and vanilla should hold as set. You could set the variable in your template this way also.